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Reproductive and Vegetative Organs of Browniea gen. n. (Nyssaceae) from the Paleocene of North America

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We recognize a new genus of Nyssaceae on the basis of abundant foliage and reproductive remains from the Paleocene of North America. Browniea gen. n. is known from leaves, inflorescences, and fruits co-occurring in at least 30 sites in Wyoming, Montana, North and South Dakota, Saskatchewan, and Alberta, ranging from Maastrichtian to uppermost Clarkforkian. The simple, serrate leaves of Browniea serrata (Newberry) comb. n. were previously referred to such diverse genera as Alnus, Amelancier, Celastrus, Eucommia, Tapiscia, and Viburnum. Inflorescences and infructescences are globose heads borne on long, slender peduncles. Each fruiting head bears numerous elongate fruits with five persistent epigynous sepals and a single style with two stigmatic arms. The stamens have globose anthers with normal slitlike dehiscence and contain prolate tricolporate pollen with microreticulate ornamentation. Although the infructescences and fruits resemble those of extant Camptotheca, Browniea is distinguished by distinct calyx lobes, more elongate germination valves, normally dehiscing anthers, smaller pollen, and leaves that are consistently serrate. These fossils, together with those of Amersinia, Cornus, and Davidia, indicate that the Cornales were an important component of midlatitude North American Paleocene vegetation.
nfructescences and fruits of extant Camptotheca and fossil Browniea. A, Camptotheca acuminata Decaisne globose infructescence of spindle-shaped fruits with apical disks and persistent styles, NYBG WP Fang 3236, Sichuan, China. B–I, Browniea serrata (Newberry) comb. n., Paleocene of Wyoming, Montana, North Dakota, and Colorado. B, Large mature infructescence, Iron Bluff, Montana, UF 18975-34975. C, Infructescence and dispersed fruits, Polecat Bench, Wyoming (USNM loc. 42041), USNM 528591. D, Infructescence from Serendipity Summit, Montana (USNM loc. 14191), USNM 528592. E, Infructescence showing long peduncle, globose core, and three attached fruits, Signal Butte Gate, Montana, UF19018-38978. F–K, Long-pedunculate infructescences and infructescences from which fruits have been shed. F, Peduncle showing a sharp bend near base, Horse Creek, Montana, UF 18969-34591. G, Long-straight peduncle, Goodman Creek, North Dakota, UF 18750-30651. H, Infructescence axis denuded of fruits, with an associated dispersed fruit, Ravenscrag, Saskatchewan, USASK 58-3054. I, Pedunculate infructescence denuded of fruits, Serendipity Summit, UF 18912-35025. J, Inflorescence on narrow peduncle, Serendipity Summit (USNM loc. 14191), USNM 528594. K, Inflorescence on narrow peduncle, Polecat Bench (USNM loc. 42041), USNM 528595. L, Extant C. acuminata inflorescence. Note narrow peduncle relative to that of mature infructescence shown in A. NY: S. Tsugaru 7721. cult. Kyoto, Pref. Japan. G–L, Browniea serrata. M, Fragmentary B. serrata infructescence showing longitudinally striate surface pattern of individual fruits, Horse Creek, Montana, UF 18969-34516. N, Dispersed B. serrata fruits, Opposite Intake, Montana, UF 18816-41494. Scale bars ¼ 1 cm; bar in G applies also to F, H; bar in J applies also to K.
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Dispersed fruits of Browniea serrata (Newberry) comb. n. from the Paleocene of Wyoming, Montana, and North Dakota. A, One of the longest specimens clearly showing three of the five calyx lobes, Horse Creek, Montana, UF 18969-34498. B, Fruit showing thick dark central portion surrounded by thin, lighter-colored lateral rims with three of the calyx lobes visible at apex. Serendipity Summit, Montana, UF 18912–35016. C, Specimen from Miles City, Montana (USGS loc. 4626), USNM 528593. D, Isolated fruit from West Bijou Creek, Colorado (DMNH loc. 2732). E, Laterally arched specimen, Serendipity Summit, UF18745-35013. F, Smaller fruit, Goodman Creek, North Dakota, UF 18750-41272. G, Fruit from Killpecker Creek, Wyoming, UF18126–41271. H, Fruit showing narrowed base and flared apex with prominent calyx lobes, Marsh, Montana, UF18977-34954. I, Fruit showing outline of the germination valve and cuplike enclosure formed by the calyx lobes, Horse Creek, UF 18969-38370. J, Fragmentary portion of fruit showing outline of the germination valve and striations of the wall, Horse Creek, Montana, UF 18969-35277A. K, Obliquely impressed specimen showing the apical end of the fruit with the dark impression of the central style and surrounding calyx lobes, Horse Creek, UF 18969-35277B. L, Dispersed fruits originally attributed to Acer trilobatum Al. Br. by Lesquereux 1878, pl. 48, f. 3a, Carbon, Wyoming, USNM 585. M, Transversely fractured, partially permineralized fruit viewed by SEM. Note trigonal outline and collapsed locule, Serendipity Summit, UF 18912-35000. N, Transverse section of a laterally compressed, partially permineralized fruit viewed by reflected light, showing a thin lateral wing on both margins of the endocarp, Serendipity Summit, UF 18912-34933. Scale bars ¼ 1 cm in A (applies also to B–H), I, L; 5 mm in J, K; 1 mm in M, N.
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REPRODUCTIVE AND VEGETATIVE ORGANS OF BROWNIEA GEN. N. (NYSSACEAE)
FROM THE PALEOCENE OF NORTH AMERICA
Steven R. Manchester
1
and Leo J. Hickey
Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611-7800, U.S.A.; and
Peabody Museum of Natural History, Yale University, New Haven, Connecticut 06520, U.S.A.
We recognize a new genus of Nyssaceae on the basis of abundant foliage and reproductive remains from the
Paleocene of North America. Browniea gen. n. is known from leaves, inflorescences, and fruits co-occurring in
at least 30 sites in Wyoming, Montana, North and South Dakota, Saskatchewan, and Alberta, ranging from
Maastrichtian to uppermost Clarkforkian. The simple, serrate leaves of Browniea serrata (Newberry) comb. n.
were previously referred to such diverse genera as Alnus, Amelancier, Celastrus, Eucommia, Tapiscia, and
Viburnum. Inflorescences and infructescences are globose heads borne on long, slender peduncles. Each
fruiting head bears numerous elongate fruits with five persistent epigynous sepals and a single style with two
stigmatic arms. The stamens have globose anthers with normal slitlike dehiscence and contain prolate
tricolporate pollen with microreticulate ornamentation. Although the infructescences and fruits resemble those
of extant Camptotheca, Browniea is distinguished by distinct calyx lobes, more elongate germination valves,
normally dehiscing anthers, smaller pollen, and leaves that are consistently serrate. These fossils, together with
those of Amersinia, Cornus, and Davidia, indicate that the Cornales were an important component of
midlatitude North American Paleocene vegetation.
Keywords: Cornales, Nyssaceae, Camptotheca, Amersinia, Paleocene, North America fossils, leaves,
infructescences, fruits, pollen.
Introduction
The order Cornales (dogwood alliance) is well represented
in Paleocene floras of midlatitude North America. Cornus is
known from leaves (Hickey 1977) and endocarps of the ‘cor-
nelian cherry’ subgroup (Crane et al. 1990; Xiang et al.
2003). Mastixia and the extinct mastixioid genus Langtonia
Reid et Chandler are known on the basis of characteristic en-
docarps from the Paleocene of Wyoming (T iffney and Haggard
1996). The most abundant representatives of the Cornales in
North American Paleocene floras have only recently been
identified. Davidia, which is endemic to China in its present-
day native distribution, is well represented by leaves and
fruits at many sites in the Fort Union Formation of Wyoming,
Montana, and North Dakota (Manchester 2002). The extinct
nyssaceous genus Amersinia, known by its infructescence
structure, fruit morphology and anatomy, and associated
foliage (Beringiaphyllum), was distributed in the Paleocene
of North America (Wyoming, Montana, North Dakota, and
Saskatchewan; Manchester et al. 1999) and in eastern Asia
from Kamchatka to northeastern China (Manchester et al.
1999; Feng et al. 2002).
Interpretation of these fossils is facilitated by increasingly
improved knowledge of the relationships among their extant
relatives. The Cornales, as currently understood, include Cor-
naceae, Curtisiaceae, Grubbiaceae, Hydrangeaceae, Hydrosta-
chyaceae, Loasaceae, Mastixiaceae, and Nyssaceae (modified
slightly from APG 1998). The Hydrangeaceae and Loasaceae
are readily distinguished from other Cornales and from Brown-
iea by capsular fruits with numerous seeds per locule. Al-
though Eyde (1988, 1997) favored the merging of Nyssaceae
and Mastixiaceae within Cornaceae s.l., we prefer to recognize
Nyssaceae, Mastixiaceae, and Cornaceae as distinct families,
as supported by both molecular sequence investigations (Fan
and Xiang 2003) and morphology. Cornaceae, together with
Alangiaceae and Curtisiaceae, have fruit stones composed
mainly of isodiametric sclereids, whereas fruit stones of Nyssa-
ceae are composed of elongate fibers.
The Nyssaceae include the extant genera Nyssa and Camp-
totheca, plus the extinct genus Amersinia (Manchester et al.
1999). In addition, Davidia is usually included in the Nyssa-
ceae if it is not placed in its own family; it is the only genus
of Cornales that lacks a nectariferous disk in the flowers.
Nyssa and Camptotheca have septate pith, whereas the pith
of Davidia and other Cornales lacks septae. Chromosome
number and configuration links Davidia and Camptotheca
(2x¼21) and distinguishes these genera from Nyssa (2x¼22;
He et al. 2004). These genera are readily distinguished by their
fruit types, which differ in wall thickness, number of locules,
and length of the germination valves.
New data from associated leaves, infructescences, fruits,
and flowers now provide the basis for recognizing yet an-
other nyssaceous genus that was abundant in the Paleocene
of the Great Plains region. The abundant foliage of this
taxon has been identified to many different genera during the
past century, most recently Eucommia serrata (Newberry)
1
Author for correspondence; e-mail steven@flmnh.ufl.edu.
Manuscript received November 2005; revised manuscript received September
2006.
229
Int. J. Plant Sci. 168(2):229–249. 2007.
Ó 2007 by The University of Chicago. All rights reserved.
1058-5893/2007/16802-0009$15.00
Brown (1962), Tapiscia serrata (Newberry) Chandrasekharam
(1974), and Dicotylophyllum anomalum (Ward) Hickey (1977;
Johnson 2002). In this article, we introduce the new genus
Browniea and present evidence for the multiple-organ recon-
struction of Browniea serrata (Newberry) comb. n., which was
common and widespread in the Paleocene of midlatitude North
America. We review its stratigraphic and geographic range and
consider the systematic affinities of this genus in relation to
other fossil and extant genera of the Nyssaceae.
Material and Methods
Fossil foliage and fruits were studied from 30 Paleocene lo-
calities in the Great Plains of the United States and Canada
(fig. 1; app. table C1). Some of these same sites also contain
fruits and foliage of two other nyssoid genera: Amersinia and
Davidia (Manchester et al. 1999; Manchester 2002). Slightly
older specimens from the latest Cretaceous, immediately be-
low the Cretaceous-Tertiary boundary, in southwestern North
Dakota were examined in the collections of the Denver Mu-
seum of Nature and Science, courtesy of Kirk Johnson. Age
assignments, according to North American Land Mammal age
correlations, are presented in appendix table C1. The precision
of these age assignments varies among the sites; however, the
primary reason for this investigation was not to assess the
precise age of each occurrence but rather to document re-
peated co-occurrence of the leaves, fruits, and flowers at dif-
ferent localities to reinforce the hypothesized multiple-organ
reconstruction of Browniea.
Leaves and fruits from our field work at Paleocene sites in
Wyoming, Montana, and the Dakotas are deposited at the
Smithsonian Institution (USNM), Washington, D.C.; the Pea-
body Museum, Yale University (YPM), New Haven, Connecti-
cut; and the Florida Museum of Natural History, University of
Florida (UF), Gainesville, Florida. Other collections examined
include those of J. S. Newberry (1868), Leo Lesquereux (1878),
Lester Ward (1885, 1887), Roland Brown (1962), Scott
Wing (1998), and Peter Wilf (2000) housed at USNM; those
of Kirk Johnson (2002), Regan Dunn, and Richard S. Barclay
(Barclay and Johnson 2004) at the Denver Museum of
Nature and Science (DMNH); the Ravenscrag collections of
James Basinger and Beth McIver (McIver and Basinger 1993)
at the University of Saskatchewan (USASK), Saskatoon; and
collections of E. W. Berry and W. A. Bell at the Geological
Survey of Canada (GSC), Ottawa. Extant Camptotheca from
Fig. 1 Geographic distribution of extinct Browniea serrata, with individual occurrences numbered according to their sequence in appendix
table C1.
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INTERNATIONAL JOURNAL OF PLANT SCIENCES
China was studied in herbaria at PE, KUN, MO, P, and
NYBG. A new collection of Camptotheca acuminata, includ-
ing twigs with both serrate and entire-margined leaves, was
made from a roadside cultivated tree in Wenshan, Yunnan,
China, and many examples of C. acuminata and a few of
Camptotheca lowreyana were observed in plantations main-
tained by Shi-You Li at Stephen F. Austin State University,
Nachadoches, Texas.
Some of the collection sites (table C1) were more informa-
tive than others in terms of the abundance and kind of speci-
mens recovered. The Serendipity Summit site in Carbon
County, Montana, provides, in addition to numerous leaves
with well-preserved venation, a few complete infructescences,
occasional infructescence axes from which fruit have all been
shed, as well as common isolated fruits. The fruits from this
site sometimes retain details of internal morphology and
anatomy. Surface detail of the fruits and leaves is particularly
well preserved in the partially baked, fine-grained sediment of
Horse Creek, Rosebud County, Montana. These fossils were
collected adjacent to an actively burning coal seam in 2002
and 2003. Marsh, Montana, is the only site that yielded flow-
ers with intact styles, stamens, and pollen.
The fossils were obtained by cleaving siltstone and shale
with a hammer and chisel in the field to expose impressions
and compressions of leaves, fruits, and occasional infructes-
cences. Details of leaf margins and petioles and features of
the fruits not exposed in the initial fracture were revealed
by carefully chipping away additional sediment with needles
while observing with a dissecting microscope. Most specimens
are preserved only as impressions, but some of the fruits from
Serendipity Summit retain internal structure that could be in-
vestigated by fracturing for scanning electron microscopy and
by serially sectioning for light microscopy. The substance of
the fossil fruits is softer than the surrounding rock, and sec-
tioning was difficult because absorption of water used to lu-
bricate the saw blade caused the fruit remains to swell and
self-destruct. Therefore, it was necessary to immerse the sec-
tions in toluene immediately after cutting or to coat them
with cyanoacrylate cement.
Pollen was recovered from a fossil flower from Marsh,
Montana, by removing a small amount of carbonaceous ma-
terial from the anther with a needle and placing it on a glass
microscope slide for maceration. Adhering carbonate was re-
moved by applying a drop of 10% HCl. The fragments were
then macerated for 10 min in a few drops of Schultz solution
(concentrated HNO
3
saturated with potassium chlorate).
The Schultz solution was then diluted with more drops of
distilled water, drawn off the slide with filter paper, and simi-
larly washed with successive drops of water. A small drop of
10% ammonia was placed on the slide while observing with
transmitted and reflected light under a dissection microscope.
The organic material began to clear very quickly, revealing
masses of pollen. When the macerate reached an orange to
yellow translucent stage, the process was halted by flooding
with more water, drawing off the water with a pipette, and
rinsing several times with more drops of water. Some of the
pollen was transferred to other glass slides and mounted in
Canada Balsam for transmission light microscopy, and the
remainder was transferred to aluminum stubs for scanning
electron microscopy.
Systematics
Order—Cornales
Family—Nyssaceae Dum.
Genus—Browniea gen. n.
Type Species—Browniea serrata (Newberry)
comb. n.
Etymology. This genus is named for paleobotanist and ety-
mologist Roland Brown (1893–1961), who preferred for
himself the nickname ‘Brownie.’ Dr. Brown devoted much
of his career to the investigation of Paleocene floras in the
Rocky Mountain and Great Plains region (Brown 1962) and
discovered many of the localities and specimens that were im-
portant for this investigation.
Generic diagnosis. Fruiting heads spheroidal, 3–5 cm in
diameter, composed of numerous closely packed fruits. Fruit
oblong-elliptic in longitudinal outline, straight or curved,
(10–) 17–28 mm long, 4.5–7 mm wide at the broadest point,
length/width ratio 3.8–4.0, base rounded, apex truncate, but
at the extreme apex flared into a weakly developed collar of
five free calyx lobes surrounding a single style. Fruit lensoid
to trigonal in transverse outline, unilocular and single seeded;
germination valve elongate, arising from the basal one-fourth
of the fruit and extending nearly to the fruit apex.
Leaves simple, petiole length 10%–30% of lamina length;
lamina elliptical, ovate, or rarely obovate, nearly symmetrical,
length 4–13 cm, width 3–10 cm, length/width ratio 0.8 : 1–
2.1 : 1; base usually cordate to rounded or acute; apex
rounded or less often obtuse or acute. Margin serrate with
evenly spaced teeth, sometimes entire margined over the basal
one-third of the lamina. Teeth simple to less commonly com-
pound, with a single subsidiary tooth; apical flank of tooth
acuminate, straight, basal flank convex to straight, sinuses
usually sharp. Venation pinnate; secondary veins in 7–10
pairs, usually semicraspedodromous, sometimes craspedodro-
mous near apex, curved, slightly irregular relative to one an-
other; basal two pairs of secondaries crowded along the
midvein; vein angles to midvein 30°–50°, rarely 90°–110° at
base; intersecondary veins absent; agrophic veins rare; tertiary
veins percurrent, mainly opposite, mostly convexly arched,
1–3 mm apart; angle to midvein obtuse, becoming less obtuse
apically; highest vein order fifth; areolation irregular in size
and shape. Venation to teeth with principal vein entering each
tooth medially; accessory vein on apical side strong; accessory
vein on the basal side variable from weak to strong.
Browniea serrata (Newberry) comb. n. (Fig. 2B–2K,
2M,2N; Figs. 3–7; Fig. 8D,8G; Figs. 9–11)
Basionym. Alnus serrata Newberry, 1868, New York Ly-
ceum of Natural History Annals, volume 9, page 55; New-
berry, 1898, page 66, plate 33, figure 1.
Synonymy. See appendix A.
Holotype. USNM 7003, figure 6A (counterpart of same
specimen ¼ YPM 11586). Collected by F. V. Hayden; Paleo-
cene Fort Union Formation. The publication by Newberry
(1898) indicates the specimen is from the banks of the Yel-
lowstone River, eastern Montana; however, the specimen
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MANCHESTER & HICKEY—EXTINCT PALEOCENE NYSSACEAE
itself is labeled as being from the Tongue River, Montana.
Apparently, the leaf specimen was collected on the bank of
the Yellowstone River near the confluence of the Tongue
River in or near the present location of Miles City, Montana.
Emended diagnosis. Infructescence a spheroidal head 30–
52 mm in diameter, consisting of a globose core 4.5–7 mm in
diameter bearing numerous closely packed fruits (fig. 2B–2E,
2F). Peduncle slender and elongate, 37–40 mm long and lack-
ing prominent bract scars. Fruits (figs. 2N,3,4G–4J)oblong-
elliptic in longitudinal outline, straight or curved, (10–) 17–28
mm long, 4.5–7 mm wide at the broadest point, length/width
ratio 3.8–4.0, base rounded, apex truncate, but at the extreme
apex flared into a weakly developed collar of five free calyx
lobes surrounding the single style. Lensoid to trigonal in trans-
verse outline, unilocular and single seeded, fruit wall 0.2–0.3
mm thick (fig. 3M,3N). Germination valve elongate, arising
from the basal one-fourth of the fruit and extending nearly to
the fruit apex.
Inflorescences unisexual, globose, 4–8 mm in diameter, borne
on long slender peduncle 1.5–4 cm. Young and/or abortive
fruits (fig. 4A–4D) U-shaped in lateral view with rounded base
and parallel sides, 4–5 mm long and 2–3 mm wide, with several
longitudinal ridges and five free calyx lobes 0.8 mm long aris-
ing from apex. A single style ca. 0.5 mm long arises from the
apex at about the same level at which the calyx lobes are situ-
ated, divided into two elongate stigmatic arms each ca. 1.2 mm
long (fig. 4B,4C). Stamens (fig. 4D,4E) arising from just
within the calyx lobes, exserted beyond the calyx, 3–4 mm
long, anthers globose, ca. 0.8 mm in diameter. Pollen grains
(fig. 5A–5F) prolate, equatorial diameter 14 mm, polar diame-
ter 18 mm, tricolporate. Tectum microreticulate, muri 0.3–0.5
mm, lumina variable in shape. Endoaperture with a complex
H-shaped thinning comprised of a small pore 2.5 mm in diame-
ter and a pair of lateral thinnings parallel to the colpus.
Leaves simple, petiole length 1.3–3.3, average 2.0 cm (n ¼ 10)
(fig. 6B,6C;fig.7B,7C;figs.9A,10E). Lamina usually elliptical
(fig. 6A,6B;fig.9A), occasionally ovate (figs. 7A,9B,11A),
rarely obovate (fig. 10A,10D
;11D), symmetrical to slightly
asymmetric, length 4.2–12.8, average 7.2 cm; width 3.2–9.6,
average 5.4 cm, length/width ratio 0.8–2.1, average 1.36, base
usually cordate (fig. 6C,6D;figs.7A,9B;fig.10C,10D) but
rarely acute (fig. 10A) or rounded (fig. 11A). Apex mostly
rounded (fig. 6A,6D,6E;fig.9C;fig.10D,10E), less often
obtuse or acute (fig. 9B), rarely emarginate. Margin serrate,
unlobed; sometimes entire margined over the basal one-third of
the lamina (fig. 6E;fig.10B,10D). Teeth evenly spaced, glan-
dular; simple (figs. 10F,11E) or in some cases compound, with
a single subsidiary tooth (fig. 9B), sinuses usually sharp; apical
flank of tooth acuminate, straight, basal flank convex to
straight, gland restricted to tip of tooth. Venation pinnate, sec-
ondary veins in 7–10, average 8, pairs, usually semicraspedod-
romous, curved, slightly irregular relative to one another; vein
angles to midvein 30°–50°,rarely90°–110° at base; intersec-
ondary veins absent; agrophic veins 0–2; tertiary veins percur-
rent, mainly opposite, mostly convexly arched, less often
sinuous, spaced 1–3 mm apart; angle to midvein obtuse, becom-
ing less obtuse apically; highest vein order fifth; areolation irreg-
ular in size and shape (figs. 9D,11E). Venation to teeth with
principal vein entering each tooth medially; accessory vein on
apical side strong; accessory vein on the basal side variable from
weak or discontinuous to strong (figs. 9D,10F,11E). Impres-
sions in fine-grained sediments show closely spaced dimples (fig.
8D,8G) interpreted as impressions by rhomboidal crystals in
the mesophyll.
Discussion
The hypothesis that these dispersed plant organs represent
the same species is based on co-occurrence of the fruits and
foliage at 30 different locations (fig. 1; table C1) and on their
collective nyssoid characters. The reconstruction of these
organs as parts of the same taxon was initially complicated by
the fact that Davidia and Amersinia (also of nyssaceous affin-
ity) occur at some of the same sites, causing potential confu-
sion of leaves corresponding to the three fruit types. Diagnostic
features of th e fossil Davidia and Amersinia representatives
were clarified with the help of anatomically preserved silicified
fruits, distinctive leaf morphology, and co-occurrence data on
these organs for many different sites in the Paleocene of North
America and Asia (Manchester et al. 1999; Manchester 2002).
The remaining widespread nyssaceous foliage type, now named
Browniea, was found to show a consistent association with
Camptotheca-like fruits and infructescences.
Given the similarity in infructescence and fruit morphology
of these fossils to those of extant Camptotheca (fig. 2A), it
initially was difficult to decide whether to assign this fossil to
the extant genus Camptotheca or to treat them separately.
Differences in all of the available organs (e.g., distinct calyx
lobes persisting in fruit, elongate rather than just apical ger-
mination valves, consistently serrate leaves typically with
sharp sinuses, anther dehiscence normal rather than by api-
cally hinging valves, and much smaller pollen) led us to place
it in a separate genus. Selected reproductive and vegetative char-
acters of Browniea, Camptotheca, and other extant and fossil
Nyssaceae are compared in table 1.
Reproductive Structures of Browniea
Browniea serrata is known from dispersed fruits, mature
infructescences, denuded infructescence axes, and rare flow-
ers. The dispersed fruits were first illustrated by Lesquereux
(1878), who misassigned them to Acer trilobatum Al. Br. (re-
figured here; fig. 3L). They received no further attention until
Brown (1962, p. 91, pl. 67, figs. 11, 12, 17) illustrated some
additional specimens as ‘probably fruits with remnants of ca-
lyces.’ Because of their inconspicuous appearance, these fos-
sils were often overlooked or discarded as uninteresting twig
fragments by collectors of fossil leaves. However, they are
consistent in their morphology, with each having a rounded
base, parallel sides, and an apex with five free calyx lobes
(figs. 2N,3A–3L).
Complete infructescence heads 3–5 cm in diameter (fig. 2B
2E,2M) reveal the source of the isolated fruits and provide
additional taxonomic characters. One of these mature heads
shows the intact peduncle, which is long and slender (fig. 2E).
This specimen, along with others from which all of the fruits
had shed (fig. 2F–2K), indicates that the full length of the pe-
duncle ranged from 1.5 to 4 cm. The peduncle does not bear
prominent scars that might be interpreted as the position of
showy bracts (cf. Davidia, Amersinia), but there are sometimes
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INTERNATIONAL JOURNAL OF PLANT SCIENCES
Fig. 2 Infructescences and fruits of extant Camptotheca and fossil Browniea. A, Camptotheca acuminata Decaisne globose infructescence of
spindle-shaped fruits with apical disks and persistent styles, NYBG WP Fang 3236, Sichuan, China. BI, Browniea serrata (Newberry) comb. n.,
Paleocene of Wyoming, Montana, North Dakota, and Colorado. B, Large mature infructescence, Iron Bluff, Montana, UF 18975-34975. C,
Infructescence and dispersed fruits, Polecat Bench, Wyoming (USNM loc. 42041), USNM 528591. D, Infructescence from Serendipity Summit,
Montana (USNM loc. 14191), USNM 528592. E, Infructescence showing long peduncle, globose core, and three attached fruits, Signal Butte Gate,
Montana, UF19018-38978. FK, Long-pedunculate infructescences and infructescences from which fruits have been shed. F, Peduncle showing a
sharp bend near base, Horse Creek, Montana, UF 18969-34591. G, Long-straight peduncle, Goodman Creek, North Dakota, UF 18750-30651. H,
Infructescence axis denuded of fruits, with an associated dispersed fruit, Ravenscrag, Saskatchewan, USASK 58-3054. I, Pedunculate infructescence
denuded of fruits, Serendipity Summit, UF 18912-35025. J, Inflorescence on narrow peduncle, Serendipity Summit (USNM loc. 14191), USNM
528594. K, Inflorescence on narrow peduncle, Polecat Bench (USNM loc. 42041), USNM 528595. L, Extant C. acuminata inflorescence. Note
narrow peduncle relative to that of mature infructescence shown in A. NY: S. Tsugaru 7721. cult. Kyoto, Pref. Japan. GL, Browniea serrata. M,
Fragmentary B. serrata infructescence showing longitudinally striate surface pattern of individual fruits, Horse Creek, Montana, UF 18969-34516. N,
Dispersed B. serrata fruits, Opposite Intake, Montana, UF 18816-41494. Scale bars ¼ 1 cm; bar in G applies also to F, H; bar in J applies also to K.
kinks or bends in these stalks (fig. 2F,2H), as in extant Camp-
totheca, suggesting maturation from a branched axis that origi-
nally bore multiple heads. In addition, some specimens with
narrower, shorter peduncles closely resemble the abortive heads
of unfertilized inflorescences, as illustrated in the modern Camp-
totheca acuminata (Chen et al. 1991, their fig. 1.3). Such abor -
tive heads were produced experimentally by bagging the
inflorescences to prevent insect pollination (Chen et al. 1991).
Browniea heads are distinguished from those of Platanaceae
(another family present in these Paleocene deposits) by the espe-
cially long peduncle and the lack of distinctive platanaceous sta-
mens or achenes.
Usually, the fruits are preserved in longitudinally compressed
condition, such that only two or three of the calyx lobes are
visible (fig. 3A–3I). However, in some cases, the apex has been
obliquely compressed to show all five lobes (fig. 4G–4I), and in
other cases, dissection of the encasing sediment demonstrated
that there were five calyx lobes (UF 18912-35014). The calyx
lobes are supplied with thick vascular bundles (fig. 3A,3I;
fig. 4G,4J), which sometimes preserve as filamentous projec-
tions when the laminar tissue of the calyx has degraded (e.g.,
figs. 2E,3B). Some specimens show clearly that there was a
central style emerging from the apex (fig. 3K). The Horse Creek
specimens preserve excellent anatomical surface detail with
Fig. 3 Dispersed fruits of Browniea serrata (Newberry) comb. n. from the Paleocene of Wyoming, Montana, and North Dakota. A, One of the
longest specimens clearly showing three of the five calyx lobes, Horse Creek, Montana, UF 18969-34498. B, Fruit showing thick dark central portion
surrounded by thin, lighter-colored lateral rims with three of the calyx lobes visible at apex. Serendipity Summit, Montana, UF 18912–35016. C,
Specimen from Miles City, Montana (USGS loc. 4626), USNM 528593. D, Isolated fruit from West Bijou Creek, Colorado (DMNH loc. 2732). E,
Laterally arched specimen, Serendipity Summit, UF18745-35013. F, Smaller fruit, Goodman Creek, North Dakota, UF 18750-41272. G, Fruit from
Killpecker Creek, Wyoming, UF18126–41271. H, Fruit showing narrowed base and flared apex with prominent calyx lobes, Marsh, Montana,
UF18977-34954. I, Fruit showing outline of the germination valve and cuplike enclosure formed by the calyx lobes, Horse Creek, UF 18969-38370. J,
Fragmentary portion of fruit showing outline of the germination valve and striations of the wall, Horse Creek, Montana, UF 18969-35277A. K,
Obliquely impressed specimen showing the apical end of the fruit with the dark impression of the central style and surrounding calyx lobes, Horse
Creek, UF 18969-35277B. L, Dispersed fruits originally attributed to Acer trilobatum Al. Br. by Lesquereux 1878, pl. 48, f. 3a, Carbon, Wyoming,
USNM 585. M, Transversely fractured, partially permineralized fruit viewed by SEM. Note trigonal outline and collapsed locule, Serendipity Summit,
UF 18912-35000. N, Transverse section of a laterally compressed, partially permineralized fruit viewed by reflected light, showing a thin lateral wing
on both margins of the endocarp, Serendipity Summit, UF 18912-34933. Scale bars ¼ 1cminA (applies also to BH), I, L; 5 mm in J, K; 1 mm in M, N.
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INTERNATIONAL JOURNAL OF PLANT SCIENCES
longitudinally aligned rows of cells and, in a few cases, clearly
show the \-shaped outline of an elongate germination valve ex-
tending nearly the full length of the fruit (fig. 3I,3J). Partially
permineralized specimens from Serendipity Summit, investi-
gated by fracturing and scanning (fig. 3M) and by serially
sectioning (fig. 3N), indicate that the fruits were rounded-
triangular in cross section and unilocular, with a fruit wall ca.
0.2–0.3 mm thick. Although these fruits were not recognized
in the comprehensive survey of the Ravenscrag macrofossil
flora (McIver and Basinger 1993), they are relatively common,
lying in the sedimentary matrix adjacent to various fossil leaves
(USASK collections reexamined by Manchester in 1999). Among
the figures in their monograph, three Browniea fruits are visible
in the right half of their plate 17, figure 1 (on the same rock as
leaves of Limnobiophyllum scutata) and another is misidentified
as T rapago (pl. 33, fig. 1).
Our description of flower and pollen morphology for B. serrata
is based exclusively on specimens from Marsh, Montana—the
only site where flowers and young developing fruits with persis-
tent attached stamens were found. Detached immature fruits
resemble the mature ones in shape and presence of short calyx
lobes (fig. 4A–4C) or, in one case (fig. 4D,4E), stamens.
Among the several immature fruits collected, most show a pair
of recurved stigmatic arms (e.g., fig. 4B,4C); it is possible that
a third stigmatic arm could be buried in the sediment and not
visible; hence, we should say ‘at least’ two stigmas. Another
specimen recovered from the same locality is similar in shape
and size but is staminate, showing three or more stamens aris-
ing from the apex. Two globose anthers are preserved, showing
longitudinal lines of dehiscence (fig. 4D,4E), and additional
stamens may be inferred from denuded filaments. Attempts
to recover pollen from the anthers of this flower failed. Appar-
ently, there were separate male and female flowers, but it is
possible that these flowers represent different stages of develop-
ment and that the species was protandrous as in extant Camp-
totheca (Chen et al. 1991). A darkened area surrounding the
base of the style and encircled by the sepal lobes appears to
represent a nectary (fig. 4B). The sepal lobes form a cup around
the apex of the fruit and appear likely to have held the nectar-
iferous secretions (fig. 3E,3H,3I;3K).
Fig. 4 Flowers and fruits of fossil Browniea and extant Camptotheca. AE, Flowers and developing fruits of Browniea serrata from Marsh,
Montana (UF loc. 18977). A, Flower showing epigynous calyx lobes, UF 34962. B, Developing fruit showing two stigmatic arms exserted beyond
the calyx lobes, UF 34969. C, Wider developing fruit with persistent calyx lobes and two stigmatic arms, UF 34973. D, Flower retaining stamens
(represented by four distinct filaments, one of which still has a clearly defined anther), UF 34971. E, Detail of a stamen arising from the edge of the
calyx rim from the flower in D. F, Extant flower of Camptotheca acuminata from the specimen in fig. 2L, showing swollen nectary, reduced calyx
lobes, and one of the stamens still attached, with a globose anther. G, Mature fruit showing three of the five calyx lobes, Tooley Creek, Montana,
UF 18745-41496. HJ, Transversely compressed calyces. H, Fragmentary counterpart of the specimen in G, showing three well-developed calyx
lobes; two more that can be inferred from the symmetry, UF 18745-41496. I, Whorl of calyx lobes viewed transversely, showing five lobes and a
central depression corresponding to the stylar projection, Bison Basin, Wyoming, UF18123-41275. J, Detached calyx with persistent stamens,
from which pollen was recovered, Marsh, Montana, UF 18977-35484. Scale bars ¼ 5mminA (applies also to BD), F; 1 mm in E; 1 cm in G;3
mm in H (applies also to I, J).
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MANCHESTER & HICKEY—EXTINCT PALEOCENE NYSSACEAE
Well-preserved pollen was recovered directly from an an-
ther of a transversely compressed specimen with intact stamens
from Marsh (fig. 4J). The ‘flower,’ which is better described
as the persistent calyx and stamens from a mature fruit, has
five connate calyx lobes of thick texture with rounded apices
and several parallel veins. Another similar isolated calyx was
recovered from Bison Basin, Wyoming (fig. 4I), but it lacks
stamens. These calyces are larger and bear thicker stamen
filaments than in the laterally compressed staminate flower
mentioned in the preceding paragraph, but they correspond in
size, shape, texture, and venation to those persisting on mature
fruits (fig. 4J). The anthers are globose and ca. 0.3 mm in diam-
eter. Counting the two intact anthers and three additional de-
nuded filaments, at least five stamens are apparent in this
specimen.
Pollen grains of Browniea are relatively small (14 mm equa-
torial diameter, 18 mm polar diameter), prolate, and tricolpo-
rate with a microreticulate exine sculpture (fig. 5). The
endoaperture has a complex H-shaped thinning comprised of
a small pore 2.5 mm in diameter and a pair of lateral thinnings
that are parallel to the colpus (fig. 5B,5C). These grains ap-
pear to match those known as dispersed pollen in the Paleo-
cene of Tongue River Member of the Fort Union Formation in
northeastern Wyoming and referred to the fossil genus Capri-
foliipites Wodehouse as Caprifoliipites paleocenicus Pocknall
and Nichols (1996).
Foliage of Browniea
Leaves of B. serrata are abundant in the Paleocene of the
Rocky Mountains and Great Plains. Because of wide varia-
tion in lamina shape and prominence of serration, they have
been placed in many different species and genera over the
years (see synonymy, app. A, and the list of previously misas-
signed specimens, app. B). The wide range of variability of
B. serrata leaves is greater than we originally expected but
corresponds closely to that which Brown (1962) recognized
in his concept of the species, which he then named Eucom-
mia serrata (Lesq.) Brown. The leaves vary from elliptic with
narrow acute bases to broad-elliptic with cordate bases. The
apex is commonly rounded (fig. 6A,6B,6D,6E; fig. 7A,7B;
fig. 9C; fig. 10A,10B) but can also be acute (fig. 9B). The
leaves are characteristically serrate, with teeth distributed
from the basal part of the lamina completely over the apex.
The consistent association with camptothecoid fruits pro-
vided the impetus for a more detailed investigation of this fo-
liage type.
Small rhomboidal crystals 30–40 mm in diameter are dis-
tributed regularly in the mesophyll of extant Camptotheca
leaves and are readily observed by transmitted light micros-
copy of unmacerated, dried leaves (fig. 8E,8F). The crystals
are scattered across the complete lamina. When preserved as
impressions in fine-grained sediment, the leaves of B. serrata
Fig. 5 Pollen from anther of calyx in fig. 4J. A, Macerated pollen clump. B, C, Two focus levels of tricolporate grain, showing parallel
thickenings at each colpus. D, Numerous grains from the same anther, SEM. E, Detail of a pollen grain in lateral view showing microreticulate
sculpture and two of the three colpi. F, Detail of microreticulate sculpture showing lumina of variable shape. Scale bars ¼ 10 mminAC, E;
50 mminD;3mminF.
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INTERNATIONAL JOURNAL OF PLANT SCIENCES
show regularly spaced dimples (fig. 8D,8G) corresponding
to the position of rhomboidal crystals in mesophyll of extant
Camptotheca. This feature along with leaf form and venation
distinguishes Browniea leaves from the various other extant
genera to which they had been assigned, like Celastrus, Eu-
commia, Tapiscia, and Populus.
Browniea, Amersinia, and Davidia were commonly sym-
patric in the Paleocene of North America, and it is not un-
common to find at least two of these genera together at a
given locality, as confirmed by fruits as well as foliage. Be-
cause the serrate leaves of Browniea, Davidia, and Beringia-
phyllum (inferred foliage of Amersinia) are similar in many
respects, it has been important to develop criteria for distin-
guishing them. Table 1 includes some of the leaf architectural
distinctions between these taxa. The shape and spacing of
the marginal teeth and of the sinuses and the development of
pectinal or agrophic veins are among the useful distinctions.
The presence of crystals in the mesophyll tissue is potentially
Fig. 6 Leaves of Browniea serrata (Newberry) comb. n. from Montana and North Dakota. A, Holotype; basionym Alnus serrata, Newberry
1898, p. 66, pl. 33, fig. 11, near confluence of Tongue and Yellowstone Rivers, Montana, USNM 7003. B, Similar leaf with intact petiole,
Goodman Creek, North Dakota, UF 18750-41266. C, Cordate, petiolate leaf from Signal Butte, Montana, UF19019–39202. DF, Goodman
Creek, North Dakota (UF loc. 18750). D, Ovate lamina with cordate base and complete petiole, UF 35138. E, Well-preserved lamina showing
teeth that continue over the rounded apex, UF 35137. F, Detail of margin from E. Scale bars ¼ 1 cm. Bar in E applies also to D.
237
MANCHESTER & HICKEY—EXTINCT PALEOCENE NYSSACEAE
Fig. 7 Variation among leaves of Browniea serrata (Newberry) comb. n. from Montana, Colorado, and South Dakota. A, Ovate lamina with
cordate base, semicraspedodromous secondary venation, and serration that continues uniformly over the rounded apex, Horse Creek, Montana,
UF 18969-34480. B, Larger leaf showing full length of petiole and wide elliptic lamina with marginal teeth distributed from base to apex, UF
18969-34479. C, Narrower elliptic lamina showing closely spaced sharp teeth and percurrent tertiary venation, UF 18969-34483. D, Lower half
of specimen with well-preserved transverse tertiary veins and finely serrated margin, West Bijou Creek, Colorado (DMNH loc. 2732), DMNH
26747. E , Narrower lamina with apparent cuneate base, North Cave Hills, South Dakota, UF 19024-39343. Scale bars ¼ 1 cm.
useful for the identification of Browniea fossils, but this fea-
ture requires careful analysis of the impression surface at rela-
tively high magnification (
320) with strongly oblique lighting.
At many locations, the sediment is too coarse grained or the
leaf surface detail has been disrupted by secondary gypsum
crystal deposition.
The ratio of petiole to lamina length is useful in distin-
guishing fossil leaves of Browniea from those of Davidia and
Beringiaphyllum, but of course this can be applied only
when the full length of the petiole is exposed. This usually re-
quires that the specimens be collected carefully in the field
(not trimmed too close to the lamina), so that the petiole,
which is usually buried within the sediment, can be exposed
by removing the obscuring sediment in the laboratory (fig. 6C,
6D; figs. 7A–7C,9A,10B). Among the Nyssaceae, a petiole
that is more than one-third the length of the lamina is likely
Fig. 8 Leaf architecture and anatomy of extant Camptotheca and fossil Browniea. AC, Camptotheca acuminata, Wenshan, Yunnan Province,
China. UF mod ref coll. 6146. A, Typical entire-margined leaf. B, Serrate leaf from the same tree. C, Detail of leaf margin, showing venation to the
teeth. D, Obliquely lit surface of fossil lamina showing dimples interpreted as idioblast impressions, from the fossil leaf in fig. 7C, UF 18969-
34483. E, F, Same leaf as B viewed by transmitted light microscopy, showing abundant translucent rhomboidal crystals. G, Detail of the inferred
idioblast impressions in the fossil lamina; same as D, UF 18969-34483. Scale bars ¼ 2:5cminA, B; 5 mm in C; 2 mm in D;1mmEG.
239
MANCHESTER & HICKEY—EXTINCT PALEOCENE NYSSACEAE
Fig. 9 Variation among leaves of Browniea serrata from Serendipity Summit, Montana (USNM loc. 14191 ¼ UF loc. 18912). A, Elliptical leaf
with rounded base and finely serrate margin. Tertiary veins are percurrent, mostly perpendicular to midvein. Composite image assembled from
images of both counterpart specimens, UF 35090. B, Larger lamina with cordate base, acute apex, and more prominent teeth. Secondary veins
craspedodromous to semicraspedodromous. Tertiary veins percurrent, mostly perpendicular to midvein, UF 35082. C, Widely elliptical lamina
with rounded apex, with small sharp teeth in basal one quarter and more prominent teeth apically, USNM 528596. D, Enlargement from B,
showing higher-order venation. Scale bars ¼ 1 cm.
to belong to Davidia or Beringiaphyllum, whereas shorter
petioles, one-tenth to one-third the length of the lamina, char-
acterize Nyssa, Camptotheca, and Browniea (table 1).
Another co-occurring genus somewhat similar in form is
the betulaceous leaf, Corylites (leaves identified as Betula ste-
vensoni and Corylus macquarryi in Brown 1962 but associ-
ated with extinct Palaeocarpinus fruits; Manchester et al.
2004). This betulaceous foliage has a similar range of shape,
pinnate craspedodromous venation, percurrent tertiary veins,
and a serrate margin. However, it is readily distinguished by
more distinctly preserved tertiary and quaternary venation,
better defined plexus of veins demarcating the tooth sinuses,
and often acuminate teeth.
Comparative Morphology
Placement of Browniea in the Cornales is supported by
simple, pinnately veined leaves, headlike inflorescences, epig-
ynous perianth, nectariferous rim surrounding the base of the
Fig. 10 Variation among leaves of Browniea serrata from Serendipity Summit, Montana, continued from fig. 9. A, Narrowly obovate lamina
with acute base and mostly uniform teeth, UF 18912-35087. B, Leaf with full length of petiole exposed. Basal part of lamina is entire margined,
apical part with conspicuous convex-convex teeth, UF 35010. C, Ovate leaf showing fine teeth at base, coarser teeth toward apex. Note the
specialized insect feeding tracts along the secondary veins and their branches, UF 34994. D, Lamina with cordate base and typical serration, UF
35077. E, Lamina showing variation in shape and prominence of teeth, UF 34995. F, Detail of margin from B. Scale bars ¼ 1cminAE;5mm
in F.
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MANCHESTER & HICKEY—EXTINCT PALEOCENE NYSSACEAE
style, endocarps with germination valves, and globose an-
thers with tricolporate pollen. The morphology of fossil and
extant Nyssa was reviewed by Eyde (1963, 1997), while that
of Davidia has been reviewed by Eyde (1963) and Manches-
ter (2002). Because of the striking similarities of fruit mor-
phology between Browniea and Camptotheca, we review
here, for comparative purposes, both the reproductive and
foliar morphology of Camptotheca.
Fig. 11 Leaves of Browniea serrata from additional Paleocene localities where fruits and/or flowers are associated. A, Polecat Bench, Wyoming
(USNM loc. 42041), USNM 528595. B, Bison Basin, Wyoming (DMNH loc. 716), DMNH 26023. C, Marsh, Montana, UF 18977-35143. D,
Signal Butte Gate, Montana, UF 19019-39195. E, Detail of serrate margin, with sharp sinuses and rounded teeth, and fine venation. Scale
bars ¼ 1cminA D; 5 mm in E.
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Table 1
Selected Reproductive and Vegetative Characters Distinguishing Browniea, Camptotheca, Nyssa, Davidia, and Amersinia
Character/taxon Browniea serrata Camptotheca Nyssa Davidia Amersinia/Beringiaphyllum
Infructescence type Globose head Globose head Solitary or in
raceme or head
Ellipsoidal head Ellipsoidal head
Fruits per head Numerous Numerous Few or 1 Few or 1 Numerous
Endocarp wall Very thin Very thin Thick Thick Thin
Style and stigma 1 style, 2 stigmatic
arms
1 style, 3 stigmatic arms 1 style, 1–2
stigmatic arms
1 style, 6–10
stigmatic lobes
1 style, 3 stigmatic arms
Mesocarp consistency Dry, thin Dry, thin Fleshy Fleshy/leathery Fleshy
Locules per fruit 1 1 (–2) 1–2 (–3) 6–10 3 (–4)
Germination valves Elongate Short, apical Short apical Elongate Short, apical
Infructescence bracts Scattered,
inconspicuous
Scattered,
inconspicuous
Scattered,
inconspicuous
Scattered, conspicuous Closely spaced in apparent
whorl, conspicuous
Sepals Apically free Apically fused Apically free to fused None Apically fused
Anther shape Globose Globose, apicifixed Globose to ellipsoidal Globose ?
Anther dehiscence Normal slitlike Apically hinging Normal slitlike Normal slitlike ?
Pollen shape Prolate Oblate to rarely prolate Oblate Prolate ?
Pollen ornamentation Microreticulate Microreticulate Microreticulate Microdimpled,
microverrucate
?
Pollen diameter,
equatorial (mm) 14 38–45 39–54 22–29 ?
Pith ? Septate Septate Solid ?
Petiole length relative
to lamina (%) 10–30 9–22 9–26 50–80 30–40
Prominent leaf
crystals
Yes Yes No Not in leaves observed by
us but reported by
Metcalfe and Chalk
?
Lamina length/width 0.8–2.1 1.4–2.5 1.4–3.3 0.9–1.7 1.0–1.9
Lamina apex Rounded Acute Acute to round Acute to obtuse Round to acute
Lamina secondary
venation Mostly
semicraspedodromous
Brochidodromous
when entire margined
to semicraspedodromous
Brochidodromous when
entire margined to
craspedodromous
Exclusively
craspedodromous
Craspedodromous,
semicraspedodromous,
and basally
brochidodromous
Pairs of
secondary veins 6–9 9–17 (Camptotheca acuminata),
6–11 (Camptotheca lowreyana)
8–14 8–12 5–9
Marginal teeth Present Rare to absent Rare to absent Present Present
Tooth shape Acute to right angle Acute to obtuse Acute to obtuse Sharp, acute to right angle Rounded, right
angle to obtuse
Sinus shape Angular, rarely round Round Round Angular Angular to less often round
Tooth spacing Closely spaced, full
length of lamina
Widely spaced, 1 or fewer per
secondary vein
Widely spaced, 1 or
fewer per secondary vein
Closely spaced, full
length of lamina
Closely spaced, confined
to apical two-thirds
of lamina
Pectinal veins Seldom Seldom Seldom Common Common
Intersecondary veins Absent Absent Occasional Rare or absent Absent
Morphology of Extant Camptotheca
Most authorities recognize just one extant species, Camp-
totheca acuminata (Ying et al. 1993). However, variation in
leaf shape, depth of bark furrows, fruit texture, and color
and morphology of young seedlings led Li (1997) to recog-
nize three species.
Camptotheca acuminata Decaisne has slightly furrowed
bark and deciduous, oval or round leaves with grayish lower
surface. Its fruits are short to long (mean 22–30 mm long)
with rugose surface, varying in color from yellow-brown to
red-brown or gray-brown. The hypocotyl is green at germi-
nation, and the cotyledons are lanceolate, pinnipalmate with
two to four pairs of secondary veins. This species is widely
planted in China as a fast-growing roadside tree and is seen
in botanical gardens elsewhere. Because of deforestation,
wild native populations are no longer known (S.-Y. Li, per-
sonal communication, 2003).
Camptotheca yunnanesis Dode has unfurrowed bark and
semideciduous elliptical leaves that are usually grayish on the
lower surface; fruits are relatively short (mean 22 mm long),
surface gray, smooth, and shiny, gray. Germination reveals a
red hypocotyl and linear cotyledons with pinnipalmate vena-
tion and two to four pairs of secondary veins. It is known
mainly from Yunnan Province, China.
Camptotheca lowreyana Li has deeply furrowed bark and
deciduous ovate leaves with often cordate bases that are
greenish and shiny on the lower surface; fruits are longer
(22–43 mm; mean 30 mm), surface smooth and shiny, gray-
brown. Hypocotyls are green at germination, cotyledons lan-
ceolate, pinninerved with six to eight pairs of secondary
veins. This species is known from populations in Guangdong
Province, China (Li 1997).
Aside from the differences summarized a bove, these three
extant taxa of Camptotheca conform in the following char-
acters. Inflorescences terminate the current shoot or some-
times are borne in leaf axils at the upper part of the shoot.
Flowers are grouped into globose heads that are borne on
long peduncles (fig. 2L). Several heads are arranged into a
raceme-like or panicle-like compound inflorescence. Ac-
cording to Chen et al. (1991), each globose head is com-
posed of 30–60 sessile flowers arranged in two-flowered
cymules, and the peduncle of each head bears three widely
spaced triangular ovate bracts that are small and caducous,
in contrast to the large showy bracts of Davidia.Itisoften
reported that heads on the upper part of the raceme are
composed of bisexual or carpellate flowers, while those
lower on the reproductive axis are male. However, detailed
observations have shown that all of the inflorescences are
composed mostly of bisexual flowers that are protandrous,
with the pistil becoming receptive ca. 5 d after the stamens
have been shed (Chen et al. 1991). In the lower part of the
raceme-like or panicle-like inflorescence, some flowers are
only staminate, with the pistil abortive to varying degrees
(Chen et al. 1991).
The calyx of Camptotheca is adnate to the ovary and has
five small free lobes that are barely recognizable at the fruit-
ing stage; the five petals are small, ephemeral, separate, and
valvately arranged. There are 10 stamens in two whorls,
with the five stamens of the outer whorl maturing first (Chen
et al. 1991). Anthers are short, rounded, and tetrasporan-
giate. We observed a consistent feature that apparently has
not been reported before: an unusual dehiscence by apical
hinging of the four lateral walls of the anther. This type of
anther dehiscence is unique to Camptotheca and is not seen
in Nyssa, Davidia, Browniea, or other Cornales. The pollen
grains are tricolporate and oblate or suboblate, ca. 35 mmin
polar diameter and 40 mm in equatorial diameter, with finely
reticulate exine (Ying et al. 1993). A prominent nectariferous
pad lies between the androecium and gynoecium. The pistil
consists of a unilocular or bilocular ovary bearing a pendu-
lous, anatropous, unitegmic ovule and a single style with
three (rarely two) stigmatic arms (Chen et al. 1991). The ma-
ture infructescence (fig. 2A) is a globose head 35–55 mm in
diameter, composed of numerous dry fruits with a thin endo-
carp and soft pericarp forming two or three longitudinal
winglike crests. The fruit may have one or two locules, each
with an apically opening germination valve that is confined
to the apical one-third of the fruit (Eyde 1963; Manchester
et al. 1999). Despite the unilocular and bilocular condition,
the gynoecium is generally tricarpellate, as indicated by three
stigmatic arms (Eyde 1963; Moser 1968).
Although Camptotheca foliage is usually entire margin ed
(fig. 8A; Ying et al. 1993), serrate leaves sometimes occur
in the seedling and stump sprout leaves o f all three species
(Li 1997). Teeth may also be encountered in a small per-
centage of leaves from the mature canopy (fig. 8B). The
teeth in Camptotheca leaves are not closely and regularly
spaced as in Davidia or B rowniea and are not as large and
prominent as those occasionally seen in Nyssa aquatica.
Each tooth is enervated by a principal vein (usually a sec-
ondary vein) that enters m edially and one or two accessory
veins. The accessory vein along the basal side o f the tooth
is weakly developed. Petioles of Camptotheca leaves are
short to medium in length, generally less than one-fourth
the length of the lamina. In this feature, they resemble
leaves of Nyssa and are distinguished from the leaves of ex-
tant and fossil species of Davidia, which u sually have long
petioles about half the length of the lamina (table 1). The shape
of the lamina is typically elliptical, with acute to rounded
bases in C. acuminata and C. yunnanensis, but is characteris-
tically ovate, with cordate to rounded bases in C. lowreyana
(Li 1997).
Leaf venation of Camptotheca varies from camptodro-
mous, in entire-margined laminae (and in the entire-margined
portions of serrate leaves), to semicraspedodromous, where
teeth are present (fig. 8A,8B). In the latter case, the second-
ary vein splits near the margin to send one arm to the tooth
and another looping to join with the supraadjacent secondary
vein (fig. 8C). By contrast, the leaves of extant and fossil Da-
vidia are serrate (entire-margined laminae are not known for
this genus) and are characterized by strictly craspedodromous
venation, with the secondary veins extending directly to teeth
(Manchester 2002).
We observed that extant C. acuminata and C. lowreyana
typically possess abundant rhomboidal crystals embedded in
the leaf. Camptotheca yunnanensis was not available for this
study. The crystals are frequently sufficiently large (30–40 mm)
to be seen by transmitted light microscopy in dried but un-
cleared leaves (fig. 8E,8F). This feature was previously noted
244
INTERNATIONAL JOURNAL OF PLANT SCIENCES
by Metcalfe and Chalk (1950, p. 749): ‘Specially large soli-
tary crystals present in the spongy tissue of Davidia and in
the palisade parenchyma of Camptotheca.’ This is a useful
characteristic to distinguish Camptotheca from Nyssa, which
lacks such prominent crystals.
Camptotheca has not been convincingly confirmed from
the fossil fruit record. The Eocene fruit named Camptotheca
crassa Reid & Chandler (1933) was later identified to Hale-
sia (Kirchheimer 1957). Anatomically preserved wood from
the Paleogene of Kyushu, Japan, provides the earliest indica-
tion of Camptotheca in the fossil record (Suzuki 1975).
Comparative Morphology of and Relationships of Browniea
Among other Nyssaceae, Davidia and Nyssa are readily dis-
tinguished from Browniea by having berry-like fruits with
woody stones that are usually thick walled and are borne ei-
ther solitary or in racemes or few-fruited heads. The globose
infructescences and elongate, nonfleshy fruits of Browniea
closely match those of Camptotheca (fig. 2A ) in size and mor-
phology, with the exception of the better developed calyx
lobes and longer germination valves in the fossil (fig. 12). In
each of the three extant Camptotheca species recognized by Li
(1997) and in Amersinia (Manchester et al. 1999), the apical
part of the calyx is expressed only as a low rim surrounding
the nectary, whereas in Browniea the calyx forms a cuplike
collar with five distinct rounded lobes that persist in both
young (fig. 4A–4C) and mature (fig. 3H,3I,3K; fig. 4G–4J)
fruits. In extant Nyssa , the five calyx lobes are distinct in
some extant species (Nyssa sylvatica and Nyssa sinensis) but
obsolete in others (Nyssa aquatica and Nyssa ogeche; Eyde
1966). Germination valves in Browniea are elongate as in Da-
vidia, running most of the length of the fruit from the base
rather than being confined to the apical one-third of the fruit,
as in Camptotheca, Nyssa, and Amersinia (fig. 12). These gen-
era are also readily distinguished in vegetative characters, par-
ticularly in characters of the leaf margin and petiole length in
relation to lamina length (table 1).
Browniea infructescences are heads similar to those of
Amersinia (Manchester et al. 1999), but the heads are glo-
bose rather than ellipsoidal, and the fruits are more elongate
and have apically free calyx lobes. Browniea fruits are elon-
gate and almost parallel sided, not obtrullate as in Amersinia.
Although similar in width to the fruits of Amersinia obtrullata,
the fruits of Browniea serrata are about twice as long (17–28
vs. 6.5–11 mm). The rounded calyx lobes at the apex (fig.
12B) allow the fruits to be distinguished from A. obtrullata,
in which the calyx appears to be completely fused without
free tips (fig. 12D).
Browniea stamens match those of extant Camptotheca
in
filament length, size of the globose anther, and mode of attach-
ment in the flower (fig. 4D,4F), but they differ significantly
in the mode of anther dehiscence. Whereas extant Campto-
theca anthers open by apically hinging valves, the stamens
observed in Browniea open by longitudinal slits in the nor-
mal fashion (fig. 4E), as do those of Nyssa and Davidia. The
androecial morphology and pollen of Amersinia remain un-
known.
Pollen of Browniea is only half the size of Camptotheca
pollen but is similar in microreticulate ornamentation. Brown-
iea pollen is prolate, in contrast to the oblate pollen generally
observed in C. acuminata (Ying et al. 1993). Prolate pollen
with microreticulate ornamentation similar to that of the
fossil has been observed in extant C. yunnanensis (unpub-
lished SEM images by S.-Y. Li, personal communication, April
2004). Prolate pollen occurs in Davidia and Nyssa, but in
those genera, the ornamentation is not microreticulate but
rugulate.
The consistently serrate leaves of Browniea are a feature
shared with Davidia and Beringiaphyllum, contrasting with
the usually entire-margined leaves of Camptotheca and Nyssa.
The sinuses between teeth are usually angular in these genera
rather than rounded, as in the toothed leaves of Nyssa and
Camptotheca. When teeth occur in Camptotheca and Nyssa,
they are usually distributed one or fewer per secondary vein,
whereas in Browniea, the teeth are more closely spaced, two
to three per secondary vein. The proportion of petiole to
lamina length is greatest in Davidia, followed by Amersinia,
Browniea, Campthotheca, and Nyssa (table 1). Pith condi-
tion remains unknown for Amersinia and Browniea, but we
hypothesize that these genera would have had septate pith
like that of Camptotheca and Nyssa, rather than the solid
pith characterizing Davidia and other Cornales.
In summary, Browniea presents a combination of charac-
ters distinct from other extant and extinct genera of Nyssa-
ceae. The full-length germination valve of Browniea is shared
with Davidia and other Cornales, contrasting with the short-
ened apical germination valve shared by Nyssa, Camptotheca,
and Amersinia. The production of numerous fruits per in-
florescence and the apparent lack of a fleshy mesocarp indi-
cate that these fruits could have been best suited for wind
and water dispersal rather than animal dispersal, like those
of Camptotheca. The small pollen size, which is less than the
20–40-mm range optimal for wind pollination (Whitehead
1969), may be an indication that the flowers were pollinated
mainly by insects rather than by wind.
Fig. 12 Fruits of extant and fossil Nyssaceae. A, Davidia antiqua
(Newberry) Manchester, with elongate germination valves. B,
Browniea serrata (Newberry) Manchester & Hickey, with elongate
germination valve, well-developed calys lobes, and two stigmatic
arms. C, Extant Camptotheca acuminata Decaisne, showing short
apical germination valve. D, Amersinia obtrullata Manchester, Crane,
Golovneva showing obovate outline and apical germination valves. E,
Extant Nyssa sylvatica Marsh endocarp with fleshy part removed,
with apical germination valve opening.
245
MANCHESTER & HICKEY—EXTINCT PALEOCENE NYSSACEAE
Distribution
Browniea ranges from latest Cretaceous to latest Paleo-
cene. High-resolution megafossil plant studies across the
Cretaceous-Tertiary boundary in southwestern North Dakota
revealed lowest occurrences of the foliage (‘Dicotylophyllum
anomalum FU29’’) in the Maastrichtian, 15 m below the
boundary (DMNH loc. 428; Johnson 2002). In the same sec-
tion, fruits as well as foliage become common 1.3 m above
the Cretaceous-Tertiary boundary in the lowermost Puercan
stage of the Paleocene (DMNH loc. 2217; Johnson 2002).
Other localities included in this study are all of Paleocene
age (table C1) and appear to indicate that the species was
consistently present throughout most of that epoch. Appar-
ently, Browniea became extinct near the Paleocene-Eocene
boundary because no Eocene records are known. In the in-
tensively studied stratigraphic section across the Paleocene-
Eocene boundary in the Bighorn Basin of northwestern Wyomin g,
the leaves (‘ ‘D. anomalum’ ’) make their latest known appearance
in the lowest level of the Clarkforkian Land Mammal Stage (Cf1;
Wing 1998).
Although Browniea apparently was confined to North
America, its relationships to Chinese Camptotheca suggests
an early vicariance or dispersal event between North America
and eastern Asia. There remains a gap of nearly 55 million
years between the last known occurrences of Browniea in
North America and the present populations of Camptotheca
in China. The importance of the Beringial connection in the
early Tertiary history of Nyssaceae is indicated also by the
occurrence of both Amersinia and Davidia in the Paleocene
of both eastern Asia and western North America (Manchester
et al. 1999; Manchester 2002). Browniea occurred in mixed
broad-leaved deciduous vegetation, often accompanied by
Platanus, Macginitiea, Davidia, Cornus, Aesculus, extinct
Cercidiphyllaceae, Nordenskioldia, and Metasequoia. Cli-
matically, Browniea serrata was probably distributed in situ-
ations similar to that of extant Camptotheca. However, the
occurrence in swampy, coal-accumulating sediments suggests
that Browniea was adaptive to stream- and lake-side habitats
like the flood-tolerant extant species of the related genus
Nyssa. It may be that Browniea expired, along with many
other plants, in response to rapid environmental change, in-
cluding the marked warming at the end of the Paleocene
(Wing et al. 2005).
Acknowledgments
For help with fieldwork and access to collections, we are
indebted to James Basinger; Howard Emry, Kirk Johnson,
Zlatko Kvac
ˇ
ek, Lee Pierce, Scott Wing, and Peter Wilf. We
thank Kirk Johnson, Douglas Nichols, Peter Wilf, Scott
Wing, Terry Lott, and Hongshan Wang for helpful informa-
tion and discussion. Extant Camptotheca collections were
made with the guidance of Zhekun Zhou and Zhiduan
Chen. Shi-You Li granted access to private plantations of
Camptotheca at Stephen F. Austin State University, Nacha-
doches, Texas, and provided helpful discussion about the
morphology and distribution of the three extant species.
This work was supported in part by grants EAR 9220079
and EAR 0174295 from the National Science Foundation.
Appendix A
Synonymy for Browniea serrata
Alnus serrata Newberry, 1868, N. Y. Lyceum Nat. Hist. Ann., v. 9, p. 55; Newberry, 1898, p. 66, pl. 33, fig. 11—Holotype:
USNM 7003: Banks of the Yellowstone River near the junction of the Tongue River, Montana; Late Paleocene, Tongue River
Mbr., Fort Union Fm. (Basionym). Eucommia serrata (Newberry) Brown, 1962, U.S. Geol. Surv. Prof. Pap. 364 (part), p. 72,
pl. 44, figs. 1–6; pl. 45, figs. 2–7. Tapiscia serrata (Newberry) Chandrasekharam, 1974, Palaeontogr. Abt. B, p. 29, pl. 21,
figs. 136–138.
Dicotylophyllum anomalum (Ward) Hickey, 1977, Geol. Soc. Am. Mem. 150, p. 147, pl. 29, fig. 5; pl. 30, fig. 5; appendix
fig. 2 (right): Mercer and Morton Counties, North Dakota; Late Paleocene, Bear Den Mbr., Golden Valley Fm. McIver and
Basinger, 1993, Palaeontogr. Can. 10, p. 51–53, pl. 42, figs. 1, 2; pl. 43, figs. 1–4: Ravenscrag Butte, Saskatchewan, Canada;
Early Paleocene, Ravenscrag Fm.
Celastrus ferrugineus Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 78, pl. 34, figs. 1–4—Lectotype, here designated, USNM
313286, fig. 2: Iron Bluff, Montana; Early Paleocene, Fort Union Fm.
Celastrus taurinensis Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 79, pl. 34, figs. 5, 6—Lectotype, here designated, USNM 5346,
fig. 6: Bull Mountains, Montana; Paleocene, Fort Union Fm. Hollick, 1899, Geol. Surv. Louisiana, Prelim. Rep. 5, p. 285,
pl. 46, fig. 1 (YPM 27106), Coushatta, Louisiana; Paleocene, Wilcox Group. Also cited in Berry, 1916, U.S. Geol. Surv. Prof.
Pap. 91, p. 267, pl. 60, fig. 1. Aralia taurinensis (Ward) Sanborn, 1935 (part) Carnegie Inst. Wash. Publ. 465. Not pl. 10,
figs. 1, 2, 4, or specimens cited on p. 28.
Celastrus alnifolius Ward, 1887 (non D. Don, 1825), U.S. Geol. Surv. Bull. 37, p. 80, pl. 35, figs. 1, 2—Lectotype, here desig-
nated, USNM 5340, fig. 1: Burns Ranch, near Glendive, Montana; Paleocene, Fort Union Fm. Celastrus montanensis Knowlton
and Cockerell, 1919, U.S. Geol. Surv. Bull. 696, p. 159.
Celastrus pterospermoides Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 80, pl. 35, fig. 3–6—Lectotype, here designated, USNM
5331, fig. 5: Iron Bluff, Montana; Lower Paleocene, Fort Union Fm.
Celastrus ovatus Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 81, pl. 36, fig. 1—Holotype USNM 5335. Iron Bluff, Montana;
Lower Paleocene, Fort Union Fm.
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INTERNATIONAL JOURNAL OF PLANT SCIENCES
Celastrus grewiopsis Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 81, pl. 36, fig. 2—Holotype USNM 5336. Burns Ranch, near
Glendive, Montana; Paleocene, Fort Union Fm.
Celastrus curvinervis Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 82, pl. 36, figs. 3, 4—Lectotype, here designated, USNM 5341,
fig. 3: Burns Ranch, near Glendive, Montana; Paleocene, Fort Union Fm.
Euonymus xantholithensis Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 82, pl. 37, figs. 1, 2—Lectotype, here designated, USNM
5305, fig. 2: Burns Ranch, near Glendive, Montana; Paleocene, Fort Union Fm.
Elaeodendron serrulatum Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 83, pl. 37, figs. 3–5—Lectotype, here designated, USNM
5371, fig. 3: Burns Ranch, near Glendive, Montana; Paleocene, Fort Union Fm.
Elaeodendron polymorphum Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 84, pl. 38, figs. 1–6—Lectotype, here designated, USNM
5313, fig. 1: Burns Ranch, Montana; Paleocene, Fort Union Fm.
Grewia pealei Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 87, pl. 39, figs. 3–5—Lectotype, here designated, USNM 5310, fig. 3:
Bull Mountains, Montana; Paleocene, Fort Union Fm.
Pterospermites minor Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 95, pl. 42, figs. 1–3—Lectotype, here designated, USNM 4204,
fig. 5: Burns Ranch, near Glendive, Montana; Paleocene, Fort Union Fm. Berry, 1935, Can. Geol. Surv. Mem. 182, p. 48,
pl. 11, fig. 4: Saskatchewan, Canada; Paleocene Middle Ravenscrag Fm.
Diospyros? obtusata Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 105, pl. 49, fig. 5—Holotype USNM 4169: Seven Mile Creek,
Montana; Paleocene, Fort Union Fm.
Celastrus serratus Knowlton, 1917 (part) U.S. Geol. Surv. Prof. Pap. 101, p. 329, pl. 98, fig. 3; pl. 99, fig. 4—Lectotype, here
designated, USNM 34673, pl. 99, fig. 4: Primero, Colorado; Early Paleocene, Raton Fm.
Viburnum finale Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 115, pl. 57, fig. 5—Holotype USNM 4050: Iron Bluff, Montana;
Lower Paleocene, Fort Union Fm.
Appendix B
Revised Assignments
The following specimens, illustrated previously in the literature under other binomials, are now transferred to Browniea serrata.
Although these specimens are transferred, the indicated binomials remain in effect for other specimens, including the holo-
types.
Acer trilobatum var. productum? auct. non Al. Br.; Lesquereux, 1878, U.S. Geol. Surv. Terr. Rep. 7, p. 261. pl. 48, fig. 3a. Car-
bon, Wyoming, Paleocene.
Amelanchites similis (Newberry) McIver and Basinger, 1993, Palaeontogr. Can. 10, p. 42, pl. 29, figs. 1–5; pl. 30, fig. 3,
Ravenscrag Butte, Saskatchewan, Canada; Early Paleocene, Ravenscrag Fm. (Although these specimens represent B. serrata,
the specimen designated by McIver and Basinger as the type of the genus Amelanchites, i.e., Amelancier similis Newberry,
is actually representing Celtis aspera [Newberry] Manchester, Akhmetiev & Kodrul.)
Diospyros ficoidea auct. non Lesquereux, 1876: Ward, 1885, U.S. Geol. Surv. 6th Annu. Rep., p. 556, pl. 60, figs. 6, 7; Ward,
1887, U.S. Geol. Surv. Bull. 37, p. 105, pl. 49, figs. 3, 4. Burns Ranch and Clear Creek, Montana.
Juglans nigella auct. non Heer, 1869: Ward, 1885, U.S. Geol. Surv. 6th Annu. Rep., p. 552, pl. 40, fig. 6: Burns Ranch, near
Glendive, Montana; Paleocene, Fort Union Fm. Ward, 1887, U.S. Geol. Surv. Bull. 37, p. 33, pl. 15, fig. 1. Bell, 1949, Geol.
Surv. Can. Bull. 13, p. 55, pl. 57, fig. 5 (GSC 5493); Ravenscrag Butte, Saskatchewan; Paleocene, Ravenscrag Fm.
Celastrus taurinensis auct. non Ward, Dorf, 1938, Carnegie Inst. Wash. Publ. 508, p. 65, pl. 12, figs. 1–3; Wyoming; Medicine
Bow Fm. Berry, 1941, U.S. Geol. Surv. Prof. Pap. 193-E, p. 84, pl. 23, fig. 12; Viola, Kentucky; Eocene, Wilcox Gp. Dorf,
1942, Carnegie Inst. Wash. Publ. 508, p. 152, pl. 16, fig. 1; Lance Creek, Wyoming; Cretaceous (Maastrichtian) Lance Fm.
247
MANCHESTER & HICKEY—EXTINCT PALEOCENE NYSSACEAE
Table C1
Distribution of Paleocene Sites at Which Both Leaves and Fruits of Browniea serrata Occur
Location Museum designation Figures in this article Age Longitude, latitude Collectors
1 West Bijou Creek, CO DMNH 2732 3D,7D Lower Paleocene (Puercan;
Barclay and Johnson 2004)
W104.3269, N39.4625 R. S. Barclay
2 Big Flat Draw, WY UF 15778 Paleocene W108.8612, N41.3409 S. R. Manchester
3 Black Buttes, WY USGS 8917 Paleocene W108.65, N41.50 R. W. Brown
4 Killpecker Creek, WY UF 18126, DMNH 3G Upper Paleocene
(Clarkforkian; Wilf 2000)
W109.2532, N41.5939 S. R. Manchester,
K. Johnson
5 Bison Basin, WY UF 18123,
DMNH 716, 717, 721
4I,11B Upper Paleocene (Tiffanian; Gemmill
and Johnson 1997)
W108.1041, N42.2745 H. Emry, K. Johnson;
S. R. Manchester
6 Pats Bottom tip, WY DMNH 23711 Lower Paleocene (?Torrejonian;
R. Dunn, personal communication)
W106.8358, N41.9501 R. Dunn
7 Polecat Bench
(southeast section), WY USNM 42041 2C,2K,11A Upper Paleocene (Tiffanian 4;
Secord et al. 2006)
W108.8375, N44.8488 P. Wilf, C. Labandiera
8 Polecat Bench
(west section), WY USNM 42042 Upper Paleocene (Tiffanian 5b;
Secord et al. 2006)
W108.8724, N44.8756 P. Wilf, C. Labandiera
9 Piney Ranch, WY UF 18326 Paleocene W105.2807, N44.0695 S. R. Manchester
10 Lebo Creek, MT USGS 8547 Paleocene W110.4, 46.2 R. W. Brown
11 Serendipity Summit, MT USNM 14191, UF 18912 2D,2I,2J,3B,3E,
3M,3N,9,10
Lower Paleocene (Torrejonian;
Hickey 1980)
W108.8643, N45.0315 L. J. Hickey;
S. R Manchester,
Z. Kvacek
12 Decker, MT UF 18405 Upper Paleocene (Nichols 1999) W106.8628, N45.0120 S. R. Manchester
13 Tooley Creek, MT UF 18745 4G,4H Paleocene W106.1887, N45.2132 S. R. Manchester
14 Horse Creek, MT UF18969, YPM 2F,2M,3A,3I–3K,
7A–7C,8D,8G
Paleocene W106.1603, N45.2645 S. R. Manchester
15 Miles City River Cut, MT USGS 4626, UF18970 3C Lower Paleocene W105.8553, N46.4243 R. W. Brown;
S. R. Manchester
16 Signal Butte Gate, MT UF19018 2E,6C,11D,11E
Paleocene W105.7583, N46.3878 S. R. Manchester
17 Marsh Station, MT UF 18977, USGS 8552 3H,4A–4E ,4J,5,11C Paleocene W104.991, N46.866 R. W. Brown;
S. R. Manchester
18 Iron Bluff, MT UF 18975 2B Paleocene W104.755, N46.98 S. R. Manchester
19 Tusler, MT UF 19013, USGS 8530 Paleocene W105.6967, N46.5103 R. W. Brown;
S. R. Manchester
20 Opposite Intake, MT UF 18816 2N Paleocene W104.4983, N47.2731 S. R. Manchester
21 Burns Ranch, MT USGS 2420 Paleocene W104.408, N47.383 L. F. Ward
22 North Cave Hills, SD UF 19023 7E Paleocene (Stanley 1965) W103.4515, N45.7905 S. R. Manchester
23 Table Mountain, SD UF 18824 Paleocene (Stanley 1965) W103.6867, N45.8883 S. R. Manchester
24 Goodman Creek Bluffs, ND UF 18750 2G,3F,6B,6D–6F Upper Paleocene (Hickey 1977) W102.1094, N47.3129 S. R. Manchester
25 Trenton Hill, ND UF18134, DMNH 18134 Upper Paleocene (Tiffanian; Manchester 2001) W103.7864, N48.0933 Clarence Johnsrud
26 Bobsue Butte, ND DMNH 2206 Lower Paleocene (Puercan; Johnson 2002) W103.9831, N46.4595 Kirk Johnson
27 Dasgoods, ND DMNH 2217 Lower Paleocene (Puercan; Johnson 2002) W104.0047, N46.4386 Kirk Johnson
28 Pretty Ridge, ND DMNH 898 Lower Paleocene (Puercan; Johnson 2002) W103.9953, N46.3925 Kirk Johnson
29 Ravenscrag Butte, SK USASK 10, 30, 58 2H Lower Paleocene (Puercan; McIver
and Basinger 1993)
W109.02, N49.5067 J. Basinger,
E. McIver
30 Burnt Timber, ALB GSC6861 Paleocene W115.100, N51.6333 N. C. Ollerenshaw
Note. Ages refer to the inferred North American land mammal ages. Numbers in left column refer to positions on map (fig. 1).
Appendix C
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MANCHESTER & HICKEY—EXTINCT PALEOCENE NYSSACEAE
... The family Nyssaceae, sometimes included in the dogwood family Cornaceae (Kubitzki 2004), comprise three extant genera: Camptotheca Decaisne, Davidia Baillon, and Nyssa Linnaeus plus the extinct fossil genera Amersinia Manchester, Crane & Golovneva (Manchester et al. 1999) and Browniea Manchester et Hickey (Manchester and Hickey 2007). In Nyssaceae, the genus Nyssa with ca. 12 extant species is disjunctively distributed between East Asia and North America; the monotypic genera Davidia and Camptotheca are endemic to China (Qin and Phengklai 2007). ...
... Images of extant species in Figure 3(a-e) were photographed from the herbarium of the Institute of Botany (PE), the Chinese Academic Sciences using a Canon EOS 6D camera equipped with a 100 mm macro-lens system. Terminology for fruit description refers to Manchester and Hickey (2007) and Manchester et al. (1999). ...
... The studied infructescences are head-like, comprised of closepacked fruits (Figure 2 (a-c)-), bearing a close resemblance to the family Nyssaceae. Fruit morphology in Nyssaceae is quite distinctive (Eyde 1963), the detailed morphological comparison of vegetative and productive organs among fossil and extant genera of Nyssaceae was summarised by Manchester and Hickey (2007). In Nyssaceae, our fossil specimens can be easily distinguished by its head-like infructescence and single dispersed fruits from the extant genera Nyssa and Davidia, since Nyssa shows several clustered fruits and Davidia only present a single drupaceous fruit. ...
Article
Camptotheca Decaisne, an endemic genus with three species confined in central and southern China, is medically important for its anticancer effects. Fossil records indicate extinct genera Amersinia Manchester, Crane & Golovneva and Browniea Manchester et Hickey represented Palaeogene members of the Nyssaceae family resembling extant Camptotheca Decaisne. However, no fossil record of Camptotheca is reported until now. Here we present the first fossil of Camptotheca based on infructescences and fruits from the late Miocene of southwestern China, which is within its modern indigenous region. The fossils represented by drupaceous fruits with distinctive characters conform to Camptotheca and are distinguishable from the previous extinct genera Amersinia and Browniea, and extant genera Davidia and Nyssa of the family Nyssaceae s.s. This finding represents the first occurrence of the extant genus Camptotheca and deepens the fossil history of ‘happy trees’ back to late Miocene. It demonstrates by late Miocene, Camptotheca had inhabited in the current endemic region where it has survived to the present day.
... Pl.: 6, 26. 1760 The distinctive fossil foliage of the Palaeocene sediments of North America named initially as Alnus serrata Newberry (1868) was revised and formed a distinct fossil-genus Browniea Manchester & Hickey (2007). However, the fossil generic name is preoccupied by the generic name of well-known extant plant, Brownea Jacquin (1760) of Fabaceae, conserved with that spelling. ...
Article
Eight new generic replacement names were validated. The new fossil wood generic name Alloceltidoxylon is validated to replace later homonym, Scottoxylon Wheeler & Manchester (non Scotoxylon Vogellehner). The new fossil generic name Allonymphaea is proposed to replace later homonym, Thiebaudia M. Chandler (non Thiebautia Colla nec Thibaudia Ruiz et Pavon ex Jaume St.-Hilaire), based on leaf remains. The new fossil generic name Arecocaryon, based on fruit remains, is proposed to replace the later homonym Friedemannia M.E. Collinson, Manchester& V. Wilde (non Friedmannia Chantanachat & Bold, Algae). The new fossil wood generic name Paralnoxylon is validated to replace later homonym, Cantia Stopes (non Kantia Pia). The new fossil generic name Paranyssa, based on fossil leaves, is validated to replace later homonym, Browniea Manchester & Hickey (non Brownea Jacquin). Three new generic names for extant flowering plants were validated: Komaroviopsis replaces Komarovia Korovin (non Komaroffia O. Kuntze) and Komaroviopsideae trib. nov. replaced invalid Komarovieae, Marcanodendron instead of Uladendron Marcano-Berti (non fossil Ulodendron Lindley & Hutton) and Papyrocactus replaces Toumeya Britton & Rose (non Tuomeya W.H. Harvey, Algae). The new combinations Alloceltidoxylon eocenicum, Allonymphaea rayaniensis, Arecocaryon messelense, Paralnoxylon arborescens, Paranyssa serrata, Komaroviopsis anisosperma, Marcanodendron codesuri, and Papyrocactus papyracanthus are proposed. Alloceltidoxylon, Allonymphaea, Arecocaryon, Komaroviopsis, Marcanodendron, Paralnoxylon, Paranyssa, Papyrocactus, new replacement generic names, Komaroviopsideae trib. nov.
... Note that species with asterisks also have been collected from the Maastrichtian Vermejo Formation in the Raton Basin or adjacent Cañon-City Florence Basin, which were not differentiated in Knowlton's (1917) and Lee's (1917) monographs. This compilation is based upon additional collections and taxonomic revisions that followed publication of Knowlton's (1917) original monograph (Brown 1962;Hickey 1977;Wolfe & Upchurch 1987;Johnson 2002;Johnson & Hickey 1990;Barclay et al. 2003;Barclay & Johnson 2004;Johnson et al. 2003;Manchester & Hickey 2007;Manchester 2014;Berry 2018). Originally, Knowlton (1917) surmised that only four plant species in the Raton Basin spanned the K-Pg boundary; however, Knowlton (1917) and Lee (1917) mistakenly assumed that the K-Pg boundary was represented by a great unconformity below the Raton Formation rather than a horizon within the Sugarite coal zone of the Raton Formation (see Chapter 2). ...
The Cretaceous-Paleogene (K-Pg) mass-extinction event had a profound effect on global vegetation, with a major turnover. The post-extinction flora is typified by a recovery succession dominated by fern spores (Cyathidites and Laevigatosporites). Dispersed spores of the genus Cyathidites in this fern-spore spike interval are commonly assumed to have been produced by tropical tree ferns. However, Anemia-like schizaeaceous foliage is also known to have produced Cyathdiites (psilate, Lygodium-like trilete spores) in the Paleogene. Within the Sugarite coal zone in the Raton Formation, which contains both the K-Pg boundary and the fern-spore spike, Anemia-like schizaeaceous foliage currently classified as A. elongata (Newberry) Knowlton is associated with Cyathidites spores. As no other fern megafossil that has been collected from the Sugarite coal zone is known to have both survived the K-Pg mass-extinction event and to have been capable of producing spores of the dispersed spore genus Cyathidites, it is hypothesized that A. elongata produced these spores. A. elongata is found alongside species with a strong affinity to Lauraceae, which dominates the post-extinction dicot angiosperm flora in the Raton Basin. Lauraceous pollen typically is not preserved in the fossil record. Therefore, the orthodox concept of an earlier, fern-dominated recovery interval followed by a later phase of angiosperm recovery, which is principally based on palynology, is questioned. Reevaluation of the classic model for plant recovery in the Raton Basin, which was based upon the pattern of plant recolonization of the Krakatau islands following the 1883 volcanic eruption, provides support for the novel concept that recolonization by Lauraceae may have preceded or, more conservatively, coincided with recolonization by schizaeaceous (Cyathidites-producing) or thelypteridaceous (Laevigatosporites-producing) ferns.
... Five nodes of the phylogeny were constrained by fossils in the divergence time dating analysis. The root crown age of the phylogenetic tree (referred to as node 1) including outgroups (Camptotheca and Davidia) was The morphology of Browniea fossil exhibits similarity to Camptotheca in fruitescence and fruit shape (i.e., elongate fruits born in heads) and similarity to Davidia (i.e., toothed leaves and elongated germination valves in fruits like other cornalean taxa) (Manchester & Hickey, 2007), thus likely representing the stem of Camptotheca-Nyssa-Davidia. However, if one emphasizes the fruit shape and inflorescence, Browniea appears to be more similar to Camptotheca. Thus, it could represent the stem of Camptotheca. ...
Article
Nyssa (Nyssaceae, Cornales) represents a classical example of the well‐known eastern Asian‐eastern North American floristic disjunction. The genus consists of three species in eastern Asia, four species in eastern North America, and one species in Central America. Species of the genus are ecologically important trees in eastern North American and eastern Asian forests. The distribution of living species and a rich fossil record of the genus make it an excellent model for understanding the origin and evolution of the eastern Asian‐eastern North American floristic disjunction. However, despite the small number of species, relationships within the genus have remained unclear and have not been elucidated using a molecular approach. Here we integrate data from 48 nuclear genes, fossils, morphology, and ecological niche to resolve species relationships, elucidate its biogeographic history, and investigate the evolution of morphology and ecological niches, with the goal toward a better understanding of the well‐known EA‐ENA floristic disjunction. Results showed the Central American (CAM) N. talamancana was sister to the remaining species, which were divided among three, rapidly diversified subclades. Estimated divergence times and biogeographic history suggested Nyssa had an ancestral range in Eurasia and western North America in the late Paleocene. The rapid diversification occurred in the early Eocene, followed by multiple dispersals between and within the Erasian and North American continents. The genus experienced two major episodes of extinction in the early Oligocene and end of Neogene, respectively. The Central American N. talamancana represents a relic lineage of the boreotropical flora in the Paleocene/Eocene boundary that once diversified in western North America. The results supported the importance of both the North Atlantic land bridge and the Bering land bridge (BLB) for the Paleogene dispersals of Nyssa and the BLB for the Neogene dispersals and the role of Central America as refugia of the Paleogene flora. The total‐evidence based dated phylogeny suggested that the pattern of macroevolution of Nyssa coincided with paleoclimatic changes. We found a number of evolutionary changes in morphology (including wood anatomy and leaf traits) and ecological niches (precipitation and temperature) between the EA‐ENA disjunct, supporting ecological selection driving trait evolutions following geographic isolation. We also demonstrated challenges in phylogenomic studies of lineages with rapid diversification histories. The concatenation of gene data can lead to inference of strongly supported relationships incongruent with the species tree. However, conflicts in gene genealogies did not seem to impose a strong effect on divergence time dating in our case. Furthermore, we demonstrated that rapid diversification events may not be recovered in divergence time dating analysis using BEAST if critical fossil constraints of the relevant nodes are not available. Our study provides an example of complex bi‐directional exchanges of plants between Eurasia and North America in the Paleogene but “out of Asia” migrations in the Neogene to explain the present disjunct distribution of Nyssa in EA and ENA. This article is protected by copyright. All rights reserved.
... In comparison, the overbank facies is more strongly dominated by dicot angiosperms and the modern relatives of common overbank morphotypes such as Platanites marginata (SJ-71) and Browneia serrata (SJ-78) that commonly inhabit disturbed lake and streamside environments (Stromberg 2001;Manchester and Hickey 2007), as would be expected in downstream and lateral bar forms in a braided stream. ...
Article
Earliest Paleocene megafloras from North America are hypothesized to be low diversity and dominated by long-lived cosmopolitan species following the Cretaceous/Paleogene (K/Pg) mass extinction. However, megafloras used to develop this hypothesis are from the Northern Great Plains (NGP) of North America, and relatively little is known about floras from southern basins. Here, we present a quantitative analysis of an earliest Paleocene megaflora (<350 kyr after K/Pg boundary) from the Ojo Alamo Sandstone in the San Juan Basin (SJB), New Mexico. The megaflora, comprising 53 morphotypes, was dominated by angiosperms, with accessory taxa composed of pteridophytes, lycophytes, and conifers. Diversity analyses indicate a species-rich, highly uneven, and laterally heterogeneous flora. Paleoclimate estimates using multivariate and univariate methods indicate warm temperatures and relatively high precipitation consistent with a modern tropical seasonal forest. When compared with contemporaneous floras from the Denver Basin (DB) of Colorado and the Williston Basin (WB) of North Dakota, the SJB flora had significantly higher species richness but lower evenness. Paleoclimate estimates from the SJB were 7–14°C warmer than the estimates for the DB and WB, indicating a shift from a temperate forest in the NGP to a tropical forest in the SJB. These results demonstrate the presence of a latitudinal floral diversity and paleoclimatic gradient during the earliest Paleocene in western North America. We hypothesize that the warm, wet conditions in the earliest Paleocene SJB drove rapid rates of speciation following the K/Pg boundary, resulting in a diverse and heterogeneous flora.
... For Cornus, as we have all the major groups covering the genus distribution, we coded the distributions for each group based on their distributions. There are many fossils reported for Cornales representing lineages of Cornaceae, Alangiaceae, Curtisaceae, Grubbiaceae, Nyssaceae, Davidiaceae, and Mastixiaceae (Eyde et al., 1969;Tiffney, 1985a;Eyde, 1988Eyde, , 1997Manchester, 1994Manchester, , 1999Wheeler and Manchester, 2002;Manchester et al., , 2015Manchester and Hickey, 2007;Atkinson et al., 2016;Hayes et al., 2018). Considering the importance of fossils in reconstructing biogeographic history, we conducted the analyses in three ways: (1) using molecular phylogeny with distributional information of extant species only; (2) using molecular phylogeny and distribution of both extant and fossil species. ...
Article
The Cornales is a relatively small but morphologically diverse order in the basal position of the Asterids clade. Previous study hypothesized that the order might have undergone ancient rapid radiation during the Cretaceous when major angiosperm lineages were established. We conducted the phylogenomic analysis of Cornales using 81 plastid genome sequences with 67 newly generated in this study to test the hypothesis. This sampling represents all the families and 31 out of 48 genera in the order. Phylogenetic analyses were conducted using different datasets to examine the effects of different coding positions and character coding methods. We further conducted divergence time, diversification rate, and biogeographic analyses to understand the early evolutionary history of Cornales in space and time. Our phylogenetic analyses of four datasets (the amino acid characters, the 1st and 2nd codon positions of protein coding genes, nucleotide characters with degenerated coding method, and noncoding regions) resulted in a robust phylogeny congruent with results of previous studies, showing (((Cornaceae-Alangiaceae)-(Curtisiaceae-Grubbiaceae))-(((Nyssaceae-Davidiaceae)-Mastixiaceae)-((Hydrostachyaceae-(Hydrangeaceae-Loasaceae)))). Phylogenetic relationships within families were also well resolved. Conflicts in the placement of Hydrostachyaceae were found from analyses of two datasets, the nucleotide characters of all codon position and the 3rd codon positions, where the family was united with Loasaceae, but not strongly supported. Results from divergence time analyses suggested a mid-Cretaceous origin of Cornales followed by rapid early diversification into major clades/families within 10 million years. The early diversification of Cornales may have been facilitated by divergence in habitat and morphology following geographic dispersals. The ancestral distribution of the order was inferred as a widespread range covering Asia, Europe, North America, and Africa when including fossils in the analyses, suggesting an origin of the order likely along the Tethys Seaway where the areas were connected in the mid-Cretaceous. Inferred geographic origins of each family differed to some extent between analyses including fossils vs excluding fossils. In the analysis with extant and fossil species, the origins of the African Hydrostachyaceae and Grubbiaceae-Curtisiaceae clade were inferred to have involved two independent events, an intercontinental dispersal from the northern hemisphere to Africa and an intercontinental vicariance between the northern hemisphere and Africa, respectively. Other families were inferred to have evolved in the northern hemisphere with subsequent intercontinental dispersal(s) to other areas including to Central and South America, during their subsequent diversification. Net diversification rate analysis based on treePL dated phylogeny using MEDUSA detected a nearly 5-fold decrease in the African endemic Curtisiaceae-Grubbiaceae (CuG) clade and an increase of rate in the Hydrangeaceae-Loasaceae (HL) clade. Within HL, a decrease in the Fendlera-Jamesia clade and an increase in the Philadelphus clade were also detected. The findings are also consistent with the level of present species diversity in these lineages. Our study demonstrated the value of plastid genome in phylogenomic study, but posed an old challenge of biogeographic study with fossil data and raised caution for the synonymous substitution sites of plastid genome in phylogenomics studies.
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Leaves are the most abundant and visible plant organ, both in the modern world and the fossil record. Identifying foliage to the correct plant family based on leaf architecture is a fundamental botanical skill that is also critical for isolated fossil leaves, which often, especially in the Cenozoic, represent extinct genera and species from extant families. Resources focused on leaf identification are remarkably scarce; however, the situation has improved due to the recent proliferation of digitized herbarium material, live-plant identification applications, and online collections of cleared and fossil leaf images. Nevertheless, the need remains for a specialized image dataset for comparative leaf architecture. We address this gap by assembling an open-access database of 30,252 images of vouchered leaf specimens vetted to family level, primarily of angiosperms, including 26,176 images of cleared and x-rayed leaves representing 354 families and 4,076 of fossil leaves from 48 families. The images maintain original resolution, have user-friendly filenames, and are vetted using APG and modern paleobotanical standards. The cleared and x-rayed leaves include the Jack A. Wolfe and Leo J. Hickey contributions to the National Cleared Leaf Collection and a collection of high-resolution scanned x-ray negatives, housed in the Division of Paleobotany, Department of Paleobiology, Smithsonian National Museum of Natural History, Washington D.C.; and the Daniel I. Axelrod Cleared Leaf Collection, housed at the University of California Museum of Paleontology, Berkeley. The fossil images include a sampling of Late Cretaceous to Eocene paleobotanical sites from the Western Hemisphere held at numerous institutions, especially from Florissant Fossil Beds National Monument (late Eocene, Colorado), as well as several other localities from the Late Cretaceous to Eocene of the Western USA and the early Paleogene of Colombia and southern Argentina. The dataset facilitates new research and education opportunities in paleobotany, comparative leaf architecture, systematics, and machine learning. Keywords Angiosperms, cleared leaves, data science, fossil leaves, leaf architecture, paleobotany
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Co-evolutionary relationships of plants and fungi are of great importance for the phylogeny of both groups. Nyssa was widely distributed in the northern hemisphere during the Cenozoic. Extant species of Nyssa exhibit a disjunct distribution between eastern North America, Central America and East Asia. Here, a new species, Nyssa nanningensis Xu & Jin, is described based on fruit endocarps from the upper Oligocene Yongning Formation of the Nanning Basin, South China. This new fossil record of Nyssa expands the known palaeogeographical distribution of the genus to the low latitudes of East Asia. Associated fossil fungal fruiting bodies on Nyssa endocarps are assigned to the new fossil genus and species, Yongnicta nyssae Tobias & Maslova. This new genus is similar to some members of extant wood destructor taxa Coronophorales and Amphisphaeriales (Sordariomycetes, Ascomycota). About 3% of the Nyssa endocarps studied were affected by Yongnicta nyssae. Low frequency of fruit damage indicates that endocarps could be released from mesocarps by animals eating fleshy parts of fruits, making them potentially available to wood-destroying fungi.
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The Ravenscrag Butte flora in southwestern Saskatchewan, Canada, provides a record of an early Paleocene (Danian) forest ecosystem that followed the K-Pg boundary event. Plant macrofossil collections were investigated to assess the paleoclimate and paleoecology of the forest. An ensemble approach to climate analysis using leaf physiognomic and nearest living relative methods indicates that the forest grew under warm and wet temperate conditions, with mild frost-free winters, and did not experience a significant drying season—although some precipitation seasonality is indicated. Reconstructed leaf mass per area suggests that the woody broadleaf dicot flora had an entirely deciduous habit, despite temperature and precipitation conditions that were suitable for evergreen taxa. The reconstructed climate of the Ravenscrag Butte flora is similar to modern coastal climates with proximity to an inland sea (e.g., Croatia and Slovenia on the Adriatic Sea and Georgia on the Black Sea), suggesting that the Ravenscrag Butte flora was influenced by its proximity to the western margin of the early Paleocene Cannonball Seaway. The leaf physiognomy of the Ravenscrag Butte flora is most similar to contemporaneous fossil macrofloras from throughout western and northern North America, which suggests physiognomic homogeneity over broad latitudes during the early Paleocene, a potential consequence of vegetation reorganization after the K-Pg event.
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Specimens of Amersinia obtrullata and Beringiaphyllum pseudoantiquum in Paleocene Wuyun flora, Heilongjiang Province, Northeast China, were described and assigned to Cornaceae sensu. Infructescences formally allocated in Trochodendron sp. were reviewed and assigned to Amersinia obtrullata. Leaves described as Populus carneosa, Celastrophyllum subprotophyllum, Viburnum antiquum, V. asperum, Viburniphyllum finale, Protophyllum wuyunense, P. cf. haydenii, P. ovatifolium, Credneria inordinata were also restudied and assigned to Beringiaphyllum pseudoantiquum.