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STUDIES ON THE TAXONOMY, DISTRIBUTION, AND ABUNDANCE OF THALICTRUM TEXANUM (RANUNCULACEAE)

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Field and herbarium studies show Thalictrum texanum, a species of conservation concern, to be distinct from both T. arkansanum and T. debile. The species, which is endemic to southeast Texas, is documented to occur in eight counties. A description of the species, list of exsiccatae, distribution map, discussion of its abundance and environment, and comments on its conservation status are also included.
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Phytologia (April 2007) 89(1) 79
STUDIES ON THE TAXONOMY, DISTRIBUTION, AND
ABUNDANCE OF THALICTRUM TEXANUM
(RANUNCULACEAE)
Jason R. Singhurst
Wildlife Diversity Program
Texas Parks and Wildlife Department
Austin, Texas 78704, U.S.A.
email Jason.Singhurst@tpwd.state.tx.us
David J. Rosen
S. M. Tracy Herbarium
Department of Rangeland Ecology & Management
Texas A&M University
College Station, Texas 77843-2126, U.S.A.
William R. Carr
The Nature Conservancy of Texas
San Antonio, Texas 78295-1440, U.S.A.
and
Walter C. Holmes
Department of Biology, Baylor University
Waco, Texas 76798-7388, U.S.A.
ABSTRACT
Field and herbarium studies show Thalictrum texanum, a
species of conservation concern, to be distinct from both T.
arkansanum and T. debile. The species, which is endemic to southeast
Texas, is documented to occur in eight counties. A description of the
species, list of exsiccatae, distribution map, discussion of its abundance
and environment, and comments on its conservation status are also
included.
KEY WORDS: Ranunculaceae, Thalictrum, Texas.
Phytologia (April 2007) 89(1)
80
Currently, six species of the genus Thalictrum are recognized
as occurring in Texas (Turner et al. 2003). Two of these, T. dasycarpon
Fischer & Avé-Lallemant and T. revolutum DC., are of widespread
distribution in southeastern United States, while T. fendleri Engelm. ex
A. Gray is extensively distributed in southwestern United States and
northern Mexico. Thalictrum arkansanum B. Boivin, a poorly known
species, is limited in distribution, according to Park and Festerling
(1997), to southern Arkansas, southeastern Oklahoma, and adjacent
northeast Texas. However, the species is also reported to occur in
Angelina, Houston, and San Augustine counties in central east Texas
(Turner et al. 2003). The widespread eastern species, T. thalictroides
(L.) A. J. Eames & B. Boivin, known from only Lamar and Red River
counties in northeast Texas, has only recently been discovered in the
state (Singhurst and Holmes 1998). Finally, the subject of this report,
Thalictrum texanum (A. Gray) Small, is considered to be a Texas
endemic (Correll and Johnston 1970) and, until now, was known only
from three counties in the lower Brazos River area, northwest of the
city of Houston (Turner et al. 2003). Park and Festerling (1997), who
mention that the species is known from only two extant populations,
consider the species to be of conservation concern. The species is said
to be inconspicuous (Mahler 1983) and somewhat difficult to locate in
the field (Park and Festerling 1997). Presently, T. texanum is classified
as a plant species of concern (G2S2) (Poole et al. 2004 ), but there is
concern that it may be the same as T. debile Buckley or better treated as
a variety of that species. Park and Festerling (1997), under the
treatment of T. debile Buckley, state that T. texanum is closely related
to T. arkansanum and T. debile and that “The distinctions among the
three species should be further studied.”
The purpose of this paper is to (1) determine if there is
sufficient reason to support the recognition of Thalictrum texanum as a
species distinct from T. arkansanum and T. debile, and if so; (2) furnish
information on its distribution and population; (3) discuss the general
ecology of the species; and (4) make a recommendation as to the
conservation status of the species.
Phytologia (April 2007) 89(1) 81
METHODS
The study originated with examination of Thalictrum
specimens in three herbaria (BAYLU, SBSC, and TEX/LL) to obtain a
basic distribution of and the ecological preferences of the species. The
holotype (Hall 3) was generously loaned to the researchers by the Gray
Herbarium of Harvard University. These data were used to select
prospective sites for field studies, which were concentrated in Austin,
Brazoria, Brazos, Fayette, Grimes, Harris, Waller, and Washington
counties. Actual field investigations were undertaken from 2002 to
2004. Although not directly part of the current study, previous field
studies on T. arkansanum, which is also of conservation concern (Park
and Festerling 1997), were conducted in 2000 by the senior author in
Bowie, Delta, Lamar, and Red River counties in northeast Texas. The
specimens collected proved to be invaluable to the study reported
herewith.
Although not specifically an essential part of the present study,
the authors felt that examination of the specimens from Angelina,
Houston, and San Augustine counties in central east Texas referred to
as T. arkansanum by Turner et al. 2003 would benefit the study. These
specimens, examined at TAES and TAMU, are referable to T.
dasycarpon.
The data and specimens collected were used to determine
distribution, habitat characteristics, time of flowering, population
estimates, range of morphological variation, and for comparisons with
similar species.
Phytologia (April 2007) 89(1)
82
TAXONOMY
THALICTRUM TEXANUM (A. Gray) Small, Fl. S.E. U.S. 446.1903
Type: Texas. Harris Co.: Moist prairies, Houston, 28 Mar
1872, E. Hall 3 (Holotype: GH! Isotypes: NY, US).
Thalictrum debile Buckley var. texanum A. Gray in A. Gray et
al., Syn. Fl. N. Amer. 1: 18. 1895.
Thalictrum debile Buckley var. texana A. Gray ex E. Hall,
Plantae Texanae 3. 1873, nomen nudum.
Perennial, dioecious herbs. Roots fascicled, yellow when
fresh, brown in age [black in age according to Correll and Johnston
(1970)]. Stems ascending to erect, 14-35+ cm tall. Leaves generally
clustered near the base, generally sparse above, reduced in size from
base to apex, biternate, petioles 1-9 cm long, glabrate, irregularly
angled, primary petiolules 0.5-4.0 cm long, secondary petiolules 1-10
mm long, those of the middle leaflet substantially longer than the lateral
one, leaflets orbicular, subrotund, ovate, to reniform, 0.4-6.7(10) x 4-
6.2(9) mm, margins entire or crenate to more often (especially the
middle leaflet) shallowly to moderately cleft, bases cuneate, apices
rounded and entire, surfaces glabrous, palmately 3 (5) nerved from the
base, nerves prominent, exserted from the surface, lower surfaces
generally whitened. Inflorescence a raceme, 2-10 cm long. Flowers:
Sepals white to purplish, lanceolate to ovate, 1.7-3 mm , slightly
smaller, stamens 10-14, filaments pinkish, 0.5-2.0 mm long, thin,
anthers yellow, 1.4-1.8(2) mm long, apices pointed. Pistils ellipsoid,
green, ca. 2.2 long, ribbed, styles/stigmas pinkish, ca. 0.8 mm long,
curved, the stigmas linear, papillose, extending for most of the length of
the style. Achenes 3-4 mm (or more) long, nearly sessile, ellipsoid-
ovate, body 1.5–3.5 mm long, glabrous, slightly flattened, prominently
6–8 ribbed, beaks 0.5-1.0 mm long, straight, curved or reflexed, the
upper half prominently papillose on one side. Seeds ellipsoid,
flattened, glabrous, slightly smaller than the body of the achene.
Distribution. Clay-pan savannahs, alluvial plain terraces, and
pimple mound prairies; lower Brazos River drainage (Austin, Brazoria,
Brazos, Fayette, Grimes, Harris, Waller, and Washington counties);12–
85 m (Fig. 1).
Phenology. Flowering (late January) February to May.
Phytologia (April 2007) 89(1) 83
SPECIMENS EXAMINED: TEXAS. Austin Co.: Stephen F. Austin
State Park, 80 m from SW corner of office building near entrance of
park, 28 Feb 2003, Singhurst 14613 (BAYLU); Brazoria Co.: Nash
Ranch, W of Co. Rd. 25, about 8.7 mi. N of its intersection with TX
Hwy 35 in West Columbia, 16 Mar 2004, Rosen 2701 (BRIT, TEX);
Nowatny Prairie, S of CR 18, about 0.4 mi. E of its intersection with
Hwy 36, SE of the town of Damon, 21 Mar 2005, Rosen 3286 and
Singhurst (SBSC); Brazos Co.: College Station, Texas, 22 Mar 1948,
Park s.n. (TAMU); Frequent in moist woods along creek, 9.6 mi. SE of
College Station, 26 Mar 1949, Cory 55203 (SMU); 9 mi. S of A&M
College, 11 Mar 1949, Illige 119 (TAMU); Shady sandy soil, 8 mi. SE
of College Station, 11 Mar 1949, Whizenhunt 19 (TAMU); Damp sandy
soil partially shaded area, 6 mi. S of College Station in roadside ditch
along TX Hwy 6, 20 Mar 1957, Cypert 106 (TAMU); Moist post oak
woodland, 13 mi. S of College Station near TX Hwy 6, 15 Mar 1970,
Lonard and Bacon 2533 (SAT, SMU); Lick Creek Park SE of College
Station, 17 Apr 1986, Eaglesham 41 (TAMU); Between Lick Creek
and Alum Creek, SW 1/4 of Lick Cr. Park, ca. 0.75-0.8 airmiles SSW
of parking lot, 17 Mar 1992, Carr and Manhart 11606 (TEX-LL); Lick
Creek Park, W side of drainage ditch and E of Alum Creek ca. 500 ft.
by air SW of its jct. with another major creek (either Lick Creek or a
tributary), ca. 4.1-4.2 airmiles SSW of St. Rt. 30 bridge over Navasota
River at Ferguson Crossing, 13 Apr 1999, Carr and Linam 18084
(TEX-LL); Fayette Co.: Cummins Creek, 10 May 1849, Wright s.n.
(GH); Grimes Co.: Cemetery of St. Holland Baptist Church, TX Hwy
6, 2 mi. N of FM 2, ca. 8 mi. S of Navasota, 23 Feb 1996, Holmes 8035
(BAYLU); Ca. 500-800 ft. E of Co. Rd. 403 from a point ca. 3.7-3.8
road mi. N of its southern jct. with FM 3090, or ca. 4.1 airmiles N of
jct. FM 3090 and St. Rt. 6 (on N side of Navasota), 25 Nov 1998, Carr
and Allen 17932 (TEX-LL); Ca. 500-800 ft. E of Co. Rd. 403 from a
point ca. 3.7-3.8 road mi. of its southern jct. with F.M. 3090, or ca. 4.1
airmiles N of jct. FM 3090 and St. Rd. 6 (on N side of Navasota), 3
Mar 1999, Carr 17939 (TEX-LL); Allen property, 16 Feb 2004,
Singhurst, Carr, Allen and Loring 12717 (BAYLU); Faqua tract, 16
Feb 2004, Singhurst, Carr, Allen, and Loring 12718 (BAYLU);
Roadside of Co. Rd. 403, 1.1 mi. NW of jct. of FM 3090, NE of
Navasota, 8 Apr 2006, Whitehead 66 (TAMU); Harris Co.: Moist
prairies, Houston, 28 Mar 1872, Hall s.n. (GH); Tafton Academy
school grounds and adjacent city park, 28 Feb 2003, Johnson 1343
Phytologia (April 2007) 89(1)
84
(SBSC); Willow Park, jct. of Cliffwood and McDermed Roads, E at 10
m and 90 m under power-line, 28 Jan 2004, Singhurst and Carr 12,540
(BAYLU); Waller Co.: Picnic area, N side of US Hwy 90, 0.4 mi. W
of jct. of FM 1489, W of Brookshire, 10 Mar 1985, Brown 8492
(ASTC, SMU); Small roadside park off of Hwy 90 W of Brookshire, 3
Mar 1986, Brown 9753 (SBSC); Picnic area on N side of US Hwy. 90,
0.4 mi. W of jct. FM 1489, just W of Brookshire, 26 Mar 1992, Carr
and Diamond 11657 (TEX-LL); N side of US Hwy 90, 0.4 mi. W of
jct. FM 1489, just W of Brookshire, 21 Mar 1994, Carr and Wolfe
13355 (TEX-LL); 2 mi. NW of Pattison, from intersection of Garrett
Rd. and Buller Rd., head N 0.3 mi. to where Dry Branch crosses Buller
Rd., 6 Apr 2003, Johnson 1519 (SBSC); Ca. 0.3 mi. N of jct. of Garrett
Rd. and Buller Rd., where Buller Rd. crosses Dry Branch, E side of
Buller Rd., 28 Jan 2004, Singhurst and Carr 12541 (BAYLU);
Washington Co.: Washington Cemetery, Washington Cemetery Rd.,
0.9-1.0 road mi. E of jct. TX Hwy 105, 17 Feb 2003, Singhurst and
Carr 11608 (BAYLU); S side of Washington Cemetery Rd. 0.9-1.0
road mi. E of its jct. with St. Rt. 105, just W of Washington on the
Brazos State Park. 2.5-2.6 airmiles SSW of St. Rt. 105 bridge over
Brazos River, Carr and Singhurst 21545 (TEX-LL); Friden
Church/Cemetery, 6 Feb 2004, Holmes 12746 and Singhurst (BAYLU).
Phytologia (April 2007) 89(1) 85
Figure 1. Distribution of Thalictrum texanum in Texas. Counties with
dots ( ) have extant populations. The record from Fayette County is
historical, indicated by a triangle ( ).
DISCUSSION
Thalictrum texanum is regarded by Park and Festerling (1997)
as being closely related to T. debile of Alabama, Georgia, and
Mississippi, and to T. arkansanum of Arkansas, Oklahoma, and Texas.
These species are characterized by tuberous roots, reclined to erect
stems usually less than 45 cm tall, and leaflets of less than 15 mm in
size. Apparently there is considerable difficulty in distinguishing the
Phytologia (April 2007) 89(1)
86
three species, other than by distribution, which is further complicated
by a lack of herbarium specimens, particularly of T. texanum and T.
arkansanum. Park and Festerling (1997) mention that T. texanum is
sometimes treated as a variety of T. debile, and that T. arkansanum
possibly should be considered as a variety of T. debile also. The
following characters from Park and Festerling's key may be used to
distinguish the three species. Thalictrum texanum is characterized by its
erect to ascending habit and ovoid achenes with beaks 0.5–1 mm long,
while both T. debile and T. arkansanum have reclining to decumbent
stems and oblong to elliptic-lanceolate achenes with beaks 1.3–2 mm
long. Certainly the most impressive distinction involves leaflet
characteristics. The terminal leaflet of T. texanum is smaller (length: x
¯
= 6.708, range 4–10, S.D. = 1.764013, n = 12; width: x
¯ = 6.225, range
5.2–9, S.D. = 1.19782, n = 12) and has whitened lower surfaces.
Thalictrum arkansanum has larger leaflets (length: x
¯ = 12.09, range 8–
18, S.D. = 2.954908, n = 27; width: x
¯ = 13.0, range 8–20, S.D. =
2.621954, n = 27) and generally lack the whitened lower surfaces.
These characteristics, particularly the leaflet size, can be used to
consistently distinguish T. texanum from T. arkansanum. The few
specimens of T. debile examined had terminal leaflets that closely
approximated those of T. arkansanum, suggesting uncertainty as to the
distinction of T. arkansanum. This disposition agrees with the
assessment discussed in Diggs et al. (1999). Thus, it is recommended
that T. texanum be considered distinct from both T. arkansanum and T.
debile.
The color of the roots is another characteristic that has been
used to distinguish Thalictrum texanum from both T. debile and T.
arkansanum. In Correll and Johnston (1970) in the key to species and in
the description, the roots of T. texanum are described as becoming
black upon drying, while those of T. arkansanum are described as
brown. Essentially, Park and Festerling (1997) make the same
statements in both the key to species and descriptions, but include T.
debile ("roots brownish"), a species not within the territorial limits of
Correll and Johnston (1970). Nonetheless, black roots have not been
detected in any specimens of Thalictrum texanum consulted in this
study. All roots were brown.
Phytologia (April 2007) 89(1) 87
Until this report, Thalictrum texanum was known from
historical locations and according to Park and Festerling (1997), only
two extant populations. These were Lick Creek Park in Brazos County
and an unnamed roadside park in Waller County. Turner et al. (2003)
listed the species from Brazos, Grimes, and Waller counties. Historical
sites included Harris County (the holotype) and an unknown location
near Cummins Creek in Fayette County, based upon an 1849 collection
made by Charles Wright. As a result of this present study, the species
has been discovered in Austin, Brazoria, and Washington counties.
Additionally, the species has been “relocated” in Harris County. To
date, the species has been confirmed to occupy 13.4 ha (33 acres) in ten
distinct populations in Austin, Brazos, Brazoria, Grimes, Harris,
Waller, and Washington counties. General locations are given in the list
of exsiccatae.
Thalictrum texanum is primarily distributed in the southeast
portions of the Blackland Prairies and Post Oak Savannah vegetational
areas at sites that may be described as transitional between the two
areas; i.e., a blending of the characteristics of the two areas. One
population (Brazoria County) is known from the Gulf Prairies and
Marshes vegetation area. Generally, the species is found to occur on
three distinct soil formations: clay-pan savannahs, alluvial plain terraces,
and pimple mound prairies. More specifically, T. texanum occurs in
woodlands and woodland margins on both uplands and creek terraces on
soils with a surface layer of sandy loam over clay-pans.
At Stephen F. Austin State Park in Austin County, Thalictrum
texanum inhabited an alluvial terrace dominated by Carya illinoinensis,
Ulmus crassifolia, and Plantanus occidentalis. Non-woody vegetation
included Carex cherokeensis, Anemone heterophylla, Nothoscordum
bivalve, Ranunculus carolinianus, and Scutellaria parvula.
In Brazoria County, Thalictrum texanum was recently
discovered on remnant prairies that are maintained by mowing and
haying. The plants were growing on the fine sandy loam soils of pimple
mounds. Pimple mounds were dominated by Agrostis elliottiana,
Agrostis hyemalis var. hyemalis, Carex meadii, Panicum sp., and
Vulpia octoflora var. octoflora. Other associates included Anagallis
minima, Anemone berlandieri, Dichondra carolinensis, Drosera
Phytologia (April 2007) 89(1)
88
brevifolia, Erigeron tenuis, Euphorbia texana, Houstonia pusilla,
Krigia dandelion, Lepuropetalon spathulatum, Nothoscordum bivalve,
Oenothera laciniata, Polygala incarnata, Scleria ciliata var. glabra,
Scutellaria parvula, Silphium gracile, and Triodanis perfoliata var.
perfoliata.
At Lick Creek Park in Brazos County, the species occurred along
the margins of mostly deciduous woodland on an alluvial terrace, in partial
shade of Quercus nigra, Ulmus sp., and Ilex vomitoria. Other vegetation
included Carex cherokeensis, Tridens flavus, Elephantopus carolinianus,
Salvia lyrata, Verbesina virginica, and Schizachyrium scoparium.
At the Allen Ranch in Grimes County, the species occurred in
abundance along the margins of upland woodlands dominated by Quercus
stellata and Juniperus virginiana. Shrub components included Ilex
vomitoria, Callicarpa americana and Vaccinium arboreum. During the
springtime, margins of the woodlands were dominated by Carex
complanata and in the fall by Schizachyrium scoparium. The surface layer
of the soil is slightly acidic fine sandy loam, while the upper part of the
subsoil is slightly acid, nearly impermeable clay that ultimately produced
a perched water table during the wet season (December to March). This
combination keeps the soils very moist during periods of active growth of
Thalictrum texanum and at the same time limits root penetration.
At the Washington Cemetery in Washington County, Thalictrum
texanum occurred on a clay-pan savanna site dominated by mostly
Quercus stellata subtended by small mottes of Ilex vomitoria and
occasional clumps of Schizachyrium scoparium, Saxifraga texana, and
Claytonia virginica.
SUMMARY
Based upon our findings, it is recommended that Thalictrum
texanum be considered distinct from both T. debile and T. arkansanum,
which may be conspecific. It is further suggested that T. texanum be
considered to be of conservation concern, largely on the basis of the
limited number of extant populations.
Phytologia (April 2007) 89(1) 89
ACKNOWLEDGEMENTS
The authors are grateful to the herbaria whose specimens, in
part, made this study possible and to Gail Allen, who granted access to
her land in Grimes County. Both Dan Johnson and Larry Brown of
SBSC very graciously provided information on the occurrence of
Thalictrum texanum in Harris and Waller counties. We are also very
thankful to the manuscript reviewers, Jackie Poole and David Riskind.
LITERATURE CITED
Correll, D. S. and M. C. Johnston. 1970. Manual of the vascular plants
of Texas. Texas Research Foundation, Renner. 1881 pp.
Diggs, G. M., Jr., B. L. Lipscomb, and R. J. O’Kennon. 1999.
Shinners & Mahler’s illustrated flora of north central Texas.
Sida, Bot. Misc. 16, Botanical Research Institute of Texas,
Fort Worth. 1626 pp.
Mahler, W. F. 1983. Rediscovery of Hymenoxys texana and
notes on two other Texas endemics. Sida. 10(1): 87-91.
Park, M. M. and D. J. Festerling, Jr. 1997. Thalictrum. In: Flora of
North America Editorial Committee. Flora of North America,
Vol. 3. Magnoliophyta: Magnoliidae and Hamamelidae. Oxford
University Press, New York. pp. 258-271.
Poole, J. P., J. R. Singhurst, D. M. Price and W. R. Carr 2004.
A list of rare plants of Texas. Unpub. ms. Wildlife Diversity
Program, Texas Parks and Wildlife Department, Austin, Texas.
Singhurst, J. R. and W. C. Holmes. 1998 [2000]. Thalictrum
thalictroides (L.) Eames and Boivin: New to Texas.
Phytologia 85: 273-275.
Turner, B .L., H. Nichols, G. Denny, and O. Doron. 2003. Atlas of
the vascular plants of Texas. Sida, Bot. Misc. 24. Botanical
Research Institute of Texas, Fort Worth. 888 pp.
ResearchGate has not been able to resolve any citations for this publication.
Thalictrum In: Flora of North America Editorial Committee Magnoliophyta: Magnoliidae and Hamamelidae
  • M M Park
  • D J Festerling
  • Jr
Park, M. M. and D. J. Festerling, Jr. 1997. Thalictrum. In: Flora of North America Editorial Committee. Flora of North America, Vol. 3. Magnoliophyta: Magnoliidae and Hamamelidae. Oxford University Press, New York. pp. 258-271
Singhurst and Carr 11608 (BAYLU); S side of Washington Cemetery Rd
  • Road Mi
road mi. E of jct. TX Hwy 105, 17 Feb 2003, Singhurst and Carr 11608 (BAYLU); S side of Washington Cemetery Rd. 0.9-1.0
A list of rare plants of Texas. Unpub. ms. Wildlife Diversity Program, Texas Parks and Wildlife Department
  • J P Poole
  • J R Singhurst
  • D M Price
  • W R Carr
Poole, J. P., J. R. Singhurst, D. M. Price and W. R. Carr 2004. A list of rare plants of Texas. Unpub. ms. Wildlife Diversity Program, Texas Parks and Wildlife Department, Austin, Texas.
TEX-LL); N side of US Hwy 90, 0.4 mi. W of jct. FM 1489, just W of Brookshire Carr and Wolfe 13355 (TEX-LL); 2 mi Johnson 1519 (SBSC); Ca. 0.3 mi. N of jct
  • Mi Of Jct
  • W Fm
  • Brookshire
mi. W of jct. FM 1489, just W of Brookshire, 26 Mar 1992, Carr and Diamond 11657 (TEX-LL); N side of US Hwy 90, 0.4 mi. W of jct. FM 1489, just W of Brookshire, 21 Mar 1994, Carr and Wolfe 13355 (TEX-LL); 2 mi. NW of Pattison, from intersection of Garrett Rd. and Buller Rd., head N 0.3 mi. to where Dry Branch crosses Buller Rd., 6 Apr 2003, Johnson 1519 (SBSC); Ca. 0.3 mi. N of jct. of Garrett Rd. and Buller Rd., where Buller Rd. crosses Dry Branch, E side of Buller Rd., 28 Jan 2004, Singhurst and Carr 12541 (BAYLU); Washington Co.: Washington Cemetery, Washington Cemetery Rd.,
Thalictrum thalictroides (L.) Eames and Boivin: New to Texas
  • J R Singhurst
  • W C Holmes
Singhurst, J. R. and W. C. Holmes. 1998 [2000]. Thalictrum thalictroides (L.) Eames and Boivin: New to Texas. Phytologia 85: 273-275.
SBSC very graciously provided information on the occurrence of Thalictrum texanum in Harris and Waller counties. We are also very thankful to the manuscript reviewers
  • Jackie Poole
  • David Riskind
  • Literature
  • D S Correll
  • M C Johnston
SBSC very graciously provided information on the occurrence of Thalictrum texanum in Harris and Waller counties. We are also very thankful to the manuscript reviewers, Jackie Poole and David Riskind. LITERATURE CITED Correll, D. S. and M. C. Johnston. 1970. Manual of the vascular plants of Texas. Texas Research Foundation, Renner. 1881 pp.
Rediscovery of Hymenoxys texana and notes on two other Texas endemics
  • W F Mahler
Mahler, W. F. 1983. Rediscovery of Hymenoxys texana and notes on two other Texas endemics. Sida. 10(1): 87-91.
9-1.0 road mi Singhurst and Carr 11608 (BAYLU); S side of Washington Cemetery Rd
  • Washington Co
Washington Co.: Washington Cemetery, Washington Cemetery Rd., 0.9-1.0 road mi. E of jct. TX Hwy 105, 17 Feb 2003, Singhurst and Carr 11608 (BAYLU); S side of Washington Cemetery Rd. 0.9-1.0