Novelties in Costa Rican Stelis (Orchidaceae: Pleurothallidinae): Two new species and a new record in the “Dracontia Group”

Abstract

Stelis dies-natalis y Stelis aenigma, pertenecientes a un grupo de especies en su mayoría Centroamericanas colocadas alternativamente en el género Dracontia, son descritas e ilustradas basadas en material vivo. Ambas se encontraron en robledales de altura en diferentes picos de la Cordillera de Talamanca en Costa Rica. La primera, S. dies-natalis, se encontró en los Cerros Buena Vista y Urán, es similar a S. hydra pero se puede distinguir por la inflorescencia relativamente corta, las flores morado oscuro con un labelo amarillo cubierto por verrugas morado oscuro, los pétalos apiculados y el labelo con un apículo brevemente acuminado. La segunda, S. aenigma, que se pensaba inicialmente que se trataría un segundo espécimen de S. dies-natalis cuando se colectó en el Cerro Utyum, pero se puede distinguir fácilmente por las inflorescencias con pocas flores que apenas supera el tamaño de la hoja, las flores rojizas, el labelo sigmoideo y la antera obtusa y cuculada. Stelis platystylis, una especie previamente conocida de México a Nicaragua, es ilustraba basada en material vivo de Costa Rica.

Full text

LANKESTERIANA 17(2): 193–202. 2017.
NOVELTIES IN COSTA RICAN STELIS (ORCHIDACEAE:
PLEUROTHALLIDINAE): TWO NEW SPECIES AND A NEW RECORD
IN THE “DRACONTIA GROUP”
AdAm P. KArremAns1,2,3 & melissA díAz-morAles1
1Jardín Botánico Lankester, Universidad de Costa Rica, P.O. Box 302-7050 Cartago, Costa Rica
2Naturalis Biodiversity Center – Leiden University, The Netherlands
3Author for correspondence: adam.karremans@ucr.ac.cr
AbstrAct. Stelis dies-natalis and Stelis aenigma, belonging to a group of mostly Middle American species
alternatively placed in genus Dracontia, are described and illustrated based on living material. They were both
found in oak forests at high elevations on diverse peaks of the Talamanca mountain range in Costa Rica. The
rst, S. dies-natalis, was found on Cerro Buena Vista and Cerro Urán, and is somewhat similar to S. hydra but
can be distinguished by the relatively short inorescence, the dark purple owers with a yellow lip covered by
dark purple warts, the apiculate apex of the petals and the lip with a shortly acuminate apicule. The second, S.
aenigma, was initially believed to be a specimen of S. dies-natalis when it was collected on Cerro Utyum, but it
can be easily distinguished by the few-owered inorescence that barely exceeds the leaf, the reddish owers,
the sigmoid lip and the cucullate, obtuse anther. Stelis platystylis, a species previously known from Mexico to
Nicaragua is illustrated based on living material from Costa Rica.
resumen. Stelis dies-natalis y Stelis aenigma, pertenecientes a un grupo de especies en su mayoría Cen-
troamericanas colocadas alternativamente en el género Dracontia, son descritas e ilustradas basadas en mate-
rial vivo. Ambas se encontraron en robledales de altura en diferentes picos de la Cordillera de Talamanca en
Costa Rica. La primera, S. dies-natalis, se encontró en los Cerros Buena Vista y Urán, es similar a S. hydra
pero se puede distinguir por la inorescencia relativamente corta, las ores morado oscuro con un labelo
amarillo cubierto por verrugas morado oscuro, los pétalos apiculados y el labelo con un apículo brevemente
acuminado. La segunda, S. aenigma, que se pensaba inicialmente que se trataría de un espécimen de S. dies-
natalis cuando se colectó en el Cerro Utyum, pero se puede distinguir fácilmente por las inorescencias con
pocas ores que apenas supera el tamaño de la hoja, las ores rojizas, el labelo sigmoideo y la antera obtusa
y cuculada. Stelis platystylis, una especie previamente conocida de México a Nicaragua, es ilustraba basada
en material vivo de Costa Rica.
Key words: Dracontia, Stelis, S. aenigma, S. dies-natalis, S. hydra, S. platystylis.
Introduction. Luer (1986) proposed Pleurothallis
subgenus Dracontia Luer for a relatively small group
of species mostly from Middle America. The group
was transferred to a broad concept of Stelis Sw. by
Pridgeon and Chase (2001) with support of DNA
evidence (Pridgeon, Solano & Chase 2001). Convinced
that they required recognition as a distinct genus, Luer
(2004) elevated Dracontia (Luer) Luer to generic
level. Karremans (2011) suggested that Dracontia
could be kept separate from Stelis arguing that the
species formed a well recognizable natural group that
could be segregated on morphological and genetic
grounds. A broad DNA-based phylogenetic analysis
by Karremans et al. (2012) conrmed that the species
of Dracontia formed a highly supported monophyletic
group, but also that there were imbedded in Stelis s.l.
together with species placed in the genera Effusiella
Luer, Elongatia (Luer) Luer, Mystacorchis Szlach. &
Marg., Salpistele Dressler and Unciferia (Luer) Luer.
Dracontia cannot be recognized as currently dened
and on its own, and is therefore considered part of a
broad concept of Stelis (Karremans 2016).
Species of this particular group can be recognized by
their successive, frequently undetermined inorescences,
eshy owers with long, thick, three-lobed, movable
lips, convergent sepals forming a synsepal that is similar
Received 8 June 2017; accepted for publication 21 July 2017. First published online: 24 July 2017.
Licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Costa Rica License
doi: http://dx.doi.org/10.15517/lank.v17i2.29928

LANKESTERIANA 17(2). 2017. © Universidad de Costa Rica, 2017.
194 LANKESTERIANA
to the dorsal sepal, concave, obtuse, papillose petals,
a triangular column that is apically dentate and much
shorter than the lip, an incumbent, helm-like, large
anther (exceeding the column), a ventral stigma covered
by a bubble-like rostellum, and two at caudicles
(Karremans 2011, Karremans et al. 2012). They are
found from Mexico to Panama, with a single species
in the Antilles. The highest species diversity is found
in Costa Rica and Panama. Taking the two described
here into consideration, there are 25 species that can
currently be ascribed to this group, twenty of them are
known to grow in Costa Rica (Luer 1986, Karremans
2011, 2012, Karremans & Smith 2012), a key for all
species was provided by Karremans & Bogarín (2013).
Taxonomic treatment
Stelis dies-natalis Karremans & M.Díaz, sp. nov.
TYPE: Costa Rica. San José: Pérez Zeledón, Cerro de
la Muerte (Cerro Buena Vista), sobre sendero hacia an-
tenas del ICE, 9°40’52.10”N, 83°51’20.11”W, 2715 m,
bosque montano de robledales, 26 mayo 2015. M. Díaz
234, J. Alomía, N. Davin & A. P. Karremans (holotype:
JBL-spirit!; Fig. 1, 2).
Stelis dies-natalis is somewhat similar to Stelis hy-
dra (Karremans & C.M. Sm.) Karremans but can be
distinguished by the short inorescence, with the rst
ower barely reaching the leaf apex (vs. inorescence
far exceeding the leaf), owers dark purple (vs. red-
dish purple) with a yellow lip covered by dark purple
warts (vs. reddish-orange), the apex of the petals with
a small apicule (vs. not apiculate) and the lip with a
shortly acuminate apicule (vs. acute apex, without api-
cule).
Plant epiphytic, caespitose, erect, up to 26 cm tall.
Roots basal, liform, exuosus, slender, ca. 1 mm in
diameter. Ramicauls terete, slender, 1.8–15.5 cm long,
1–2 mm in diameter, enclosed by a thin, papyraceus,
tubular, truncate sheath on the middle third of the rami-
caul, and with two basal sheaths. Leaves suberect, co-
riaceous, sessile, elliptic, acute, emarginate, 3.9–10.2
× 0.9–2.9 cm. Inorescence successive, racemose, se-
cund, apical, from a 4–13 mm long, triangular, pros-
trate spathe, peduncle 6.3–7.5 cm long, enclosed in the
middle by a tubular sheet, 5 mm long, rachis 2.1–5.1 cm
long, barely exceeding the leaf apex at anthesis, getting
longer over time. Floral bracts short, hyaline, acute,
4–5.5 mm long. Pedicel cylindrical, 5.5–8.5 mm long,
ovary clavate, 6 mm long. Flowers ve, dark purple
with a yellow lip profusely stained with dark purple on
the warts. Dorsal sepal hirsute, involute, narrowly ovate
to lanceolate, obtuse, concave, 13.8–15.0 × 3.8–4.1 mm,
three-veined, dark purple. Lateral sepals hirsute, invo-
lute, connate to near the apex into an ovate to elliptic,
concave synsepal, acute, bid, 15.6–16.2 × 4.6–5.2 mm,
4-veined, dark purple suffused with white in the base.
Petals concave, embracing the column, obovate, papil-
lose externally, acute, with the apex involute making the
petal look obtuse in lateral view, 4.0–5.3 × 2.6–3.0 mm,
three-veined, yellowish white covered with purple pa-
pillae on the upper half and along the veins. Lip twisted
downward, eshy, three-lobed, 6.5–7.0 × 2.0–2.3 mm,
the midlobe thick, ligulate, acute, apiculate, rugose-
verrucose, yellow covered with dark purple warts, the
lateral lobes basal, suborbicular, erect, hyaline-white,
base of the lip hinged to the tip of the column-foot. Col-
umn semiterete, conical, 2.8–3.1 mm long, with a short,
thick, straight, white column-foot. Anther cap conical,
acute, rostrate, two-celled, ca. 1.2 × 0.6 mm. Pollinia
two, whale tail-like, narrowly ovate-pyriform, 0.7 mm
long, with two at caudicles.
AdditionAl mAteriAl studied: Costa Rica. San José:
Pérez Zeledón, P. I. La Amistad, Cordillera de Ta-
lamanca, sendero Herradura, que sube a la Urán
9°31’47”N, 83°35’30”W, 2600–2808 m, 6 April 1995.
R. Aguilar 3911, O. Garrote (CR!; CR-INB!).
distribution And ecology: The species is currently
known from two localities, the peaks of Urán and
Cerro Buena Vista on the north end of the Talamanca
range, growing in montane oak forest, at an elevation
of about 2700 m. (Fig. 3). It has been recorded to ow-
er in April and May.
etymology: From the Latin dies natalis (birthday, an-
niversary), commemorating Carl Luer’s 95th birthday.
Among the species belonging to the Dracontia
group, Stelis dies-natalis is recognised by the relative-
ly large plants with short, successive inorescences,
born from a small bract, the apiculate petals, the short,
thick, conspicuously apiculate lip that is yellow with
dark purple warts. It is somewhat similar to Stelis hy-
dra but can be distinguished especially by the short in-

Figure 1. Lankester Composite Dissection Plate (LCDP) of S. dies-natalis. A. Habit. B. Inorescence. C. Dissected perianth.
D. Column and lip in lateral view. E. Lip. F. Column in ventral view. G. Pollinia and anther cap. Photographs by A.
Karremans and M. Díaz-Morales based on the plant that served as type (JBL-Spirit).
LANKESTERIANA 17(2). 2017. © Universidad de Costa Rica, 2017.
KArremAns & díAz-morAles – Two new Stelis 195

LANKESTERIANA 17(2). 2017. © Universidad de Costa Rica, 2017.
196 LANKESTERIANA
Figure 2. Stelis dies-natalis. A. Habit. B. Inorescence. C. Dissected perianth. D. Column and lip in lateral view. E. Lip. F.
Column in ventral view. G. Pollinia and anther cap. Drawing by Sara Díaz Poltronieri based on the plant that served as
type (JBL-Spirit).

orescence bearing dark purple owers, with a yellow
lip covered by dark purple warts, the apex of the petals
apiculate and the lip with a shortly acuminate apicule.
Stelis aenigma Karremans & M.Díaz, sp. nov.
TYPE: Costa Rica. Puntarenas: Buenos Aires, Bue-
nos Aires, camino a Cerros Utyum, 9°19’22.54”N
83°11’30.71” W, 2748 m, bosque pluvial montano,
epíta en bosque secundario, 19 de enero 2017, A. P.
Karremans 8046, D. Bogarín, M. Cedeño, I. Chinchil-
la, M. Díaz, E. Kaes, P. Lehmann & O. Zúñiga (holo-
type: JBL-spirit!; Figs. 4, 5).
Stelis aenigma is somewhat similar to Stelis dies-
natalis but can be easily distinguished by the simulta-
neously few-owered inorescence (vs. successive, ve
or more owers), the reddish (vs. dark purple) owers,
the sigmoid lip (vs. straight) and the cucullate, obtuse
anther (vs. conical, acute).
Plant epiphytic, caespitose, erect, up to 18 cm tall.
Roots basal, liform, exuosus, slender, ca. 1 mm in
diameter. Ramicauls terete, slender, 8.0–8.7 cm long,
1–2 mm in diameter, enclosed by a thin, papyraceus,
tubular, truncate sheath extending in the middle of the
ramicaul, and with two basal sheaths. Leaves erect, co-
riaceous, sessile, elliptic, obtuse, emarginate, 6.8–8.4
× 2.6–3.0 cm. Inorescence simultaneously few ow-
ered, racemose, secund, apical, from a 11 mm long,
triangular, prostrate spathe, peduncle 6.7 cm long, en-
closed in the middle by a tubular sheet, 10 mm long, ra-
chis 1.5 cm long, apparently determinate. Floral bracts
short, hyaline, acute, 5–6 mm long. Pedicel cylindri-
cal, 7-8 mm long, ovary clavate, 4 mm long. Flowers
one to three, reddish purple with a yellow lip, some-
times stained with red. Dorsal sepal involute, ne-hir-
sute on the margins, especially near the apex, narrowly
ovate, obtuse, concave, 14.1–15.5 × 3.0–3.5 mm,
three-veined, reddish purple suffused with white in the
base. Lateral sepals involute, hirsute on the margins,
especially near the apex, connate to near the apex into
an ovate, concave synsepal, acute, emarginate, 14.0–
15.2– × 4.5–4.7 mm, four-veined, reddish purple suf-
fused with white in the base. Petals concave, embrac-
ing the column, obovate, papillose externally, acute,
with the apex involute making the petal look obtuse in
lateral view, 4.2–5.0 × 2.1–2.6 mm, three-veined, yel-
lowish white covered with purple papillae on the up-
per half and along the veins. Lip thick, ligulate, acute,
with a fold at the apical third that makes the apex bend
upward, 6.2–6.8 × 1.8–2.0 mm, rugose-verrucose, with
erect margins near the base, base of the lip hinged to
the tip of the column-foot, yellow suffused with purple
on the basal margins and the lobes. Column semiterete,
conical, 2.8–3.5 mm long, with a short, thick, slightly
incurved column foot. Anther cap cucullate, obtuse,
two-celled, ca. 0.9 × 0.6 mm. Pollinia two, whale tail-
like, narrowly ovate-pyriform, 0.5 mm long, with two
at caudicles.
other records: Costa Rica. Puntarenas: Buenos Aires,
Buenos Aires, close to the continental divide, Cerro
Arbolado, 9°19’3.23”N 83°13’16.58”W, 2435 m.
Photographed by Eberhard Kaes, the 5th of May 2014
(Fig. 6).
distribution And ecology: The only known specimens
were found close to the continental divide between
Cerro Arbolado and Cerro Utyum, southern Talamanca
range, in Costa Rica. The species is found growing in
montane oak forests between 2435 and 2748 m eleva-
tion (Fig. 3). It owered in cultivation in April and in
May in the eld.
etymology: From the Latin aenigma (enigma, riddle),
reecting the unexpected nature of the discovery of
this species which the authors initially believed would
be a specimen of Stelis dies-natalis.
LANKESTERIANA 17(2). 2017. © Universidad de Costa Rica, 2017.
KArremAns & díAz-morAles – Two new Stelis 197
Figure 3. Distribution map of Stelis dies-natalis, S. aenigma
and S. platystylis in Costa Rica.

LANKESTERIANA 17(2). 2017. © Universidad de Costa Rica, 2017.
198 LANKESTERIANA
Figure 4. Lankester Composite Dissection Plate (LCDP) of S. aenigma. A. Habit. B. Flower. C. Dissected perianth. D.
Column and lip in lateral view. E. Lip. F. Column in lateral and ventral view. G. Pollinia and anther cap. Photographs
by A. Karremans based on the plant that served as type (JBL-Spirit).

LANKESTERIANA 17(2). 2017. © Universidad de Costa Rica, 2017.
KArremAns & díAz-morAles – Two new Stelis 199
Figure 5. Stelis aenigma. A. Habit. B. Flower. C. Dissected perianth. D. Column and lip in lateral view. E. Lip. F. Column
in lateral and ventral view. G. Pollinia and anther cap. Drawing by Sara Díaz Poltronieri based on the plant that served
as type (JBL-Spirit).

When the plant that served as type of Stelis aenig-
ma was found the authors believed it would be a speci-
men of S. dies-natalis; upon owering it was clear that
it was not. It can be easily distinguished from the latter
by the simultaneously few-owered inorescence (vs.
successive, ve-plus owers), the reddish (vs. dark
purple) owers, the sigmoid lip (vs. straight) and the
cucullate, obtuse anther (vs. conical, acute). Among
the species of Dracontia it is recognised by the simul-
taneously few-owered inorescence, the long, nar-
row sepals and yellow, sigmoid lip.
Stelis platystylis (Schltr.) Solano & Soto Arenas, Icon.
Orchid. 10: t. 1097. 2008.
Bas.: Pleurothallis platystylis Schltr., Repert. Spec.
Nov. Regni Veg. 10: 395. 1912.
Syn.: Anathallis platystylis (Schltr.) Pridgeon &
M.W.Chase, Lindleyana 16: 250. 2001. Specklinia
platystylis (Schltr.) Luer, Monogr. Syst. Bot. Mis-
souri Bot. Gard. 95: 263. 2004. Effusiella platysty-
lis (Schltr.) Luer, Monogr. Syst. Bot. Missouri Bot.
Gard. 112: 107. 2007.
TYPE: Guatemala: epiphytisch auf der Höhe zwischen
Tactic und Cobán, ca. 2000 m, blühend im Dec
1906, H. von Türckheim II 1600 [holotype, B,
destroyed; illustration of type, AMES-23667,
selected as lectotype by Luer (2000)].
distri bution And eco logy: This species is appar-
ently common in Mexico and Guatemala, and less
frequent in Honduras, El Salvador, and Nicaragua.
In Costa Rica, the single known specimen of this
species was found at 1854 m in elevation close to
Tablón, south of San José. It flowered in cultivation
in January.
etymology: From the Greek platystylos, a broad style,
in reference to the conspicuous anther cap that pro-
trudes past the column apex.
costA ricAn mAteriAl stu died: San José: Desam-
parados, San Miguel, entre Tablón y Copalchí, 2
km oeste de Tablón, 9°50’07.10” N 84°01’37.20”
W, 1854 m, epífitas en bosque secundario y árboles
de potreros en bosque muy húmedo montano bajo,
2 octubre 2008, D. Bogarín 5193, R.L. Dressler, R.
Gómez, F. Pupulin, & R. Trejos (JBL-Spirit!; Figs.
7, 8).
This species has wandered in different genera
without being clearly placed amongst its closest rela-
tives. Pridgeon and Chase (2001) believed it to be an
Anathallis Barb.Rodr. However, Luer (2000) treated
it within Pleurothallis subgen. Effusia Luer, which he
latter recognized as a distinct genus under the name
Effusiella Luer. Karremans (2011) believed that the
obtuse petals, three-lobed lip, helm-shaped anther cap
that protrudes beyond the tip of the column, among
other features, were suggestive of a Dracontia afn-
ity. Such an afnity was later conrmed with DNA
data (Karremans et al. 2012). The species’ placement
within a broad sense Stelis was not news, as the both
Dracontia and Effusiella have been mostly considered
synonyms of Stelis, however we can now also point
at Stelis cobanensis (Schltr.) Pridgeon & M.W. Chase
and S. multirostris (Rchb. f.) Pridgeon & M.W. Chase
as being its closest relatives.
LANKESTERIANA 17(2). 2017. © Universidad de Costa Rica, 2017.
200 LANKESTERIANA
Figure 6. Stelis aenigma photographed in situ on Cerro
Arbolado. Photograph by E. Kaes.

LANKESTERIANA 17(2). 2017. © Universidad de Costa Rica, 2017.
KArremAns & díAz-morAles – Two new Stelis 201
Figure 7. Stelis platystylis. A. Habit. B. Flower. C. Dissected perianth. D. Column and lip in lateral view. E. Column in
lateral view. F. Pollinia and anther cap. Drawing by A. Karremans and J. Ramírez based on Bogarín 5193 (JBL-Spirit).

AcKnowledgements. This manuscript was prepared as
part of a dedicatory issue commemorating the 95th birthday
of Carl Luer, who’s extensive work on the Pleurothallidinae
is the basis for most current studies in the subtribe, includ-
ing the present. Joan Ramírez and Sara Díaz Poltronieri are
thanked for their help in the illustration of these species.
Eberhard Kaes is thanked for sharing their photographs of
these species. We are also thankful to the Costa Rican Min-
istry of Environment and Energy (MINAE) and its National
System of Conservation Areas (SINAC) for the scientic
permits.
literAture cited
Karremans, A. P. (2011). Dracontia, the little-known dragon
orchids. Orchids, 80(9), 560–566.
Karremans, A. P. (2012). Illustrations and studies in Neo-
tropical Orchidaceae. On the identity of Dracontia
pachyglossa and D. ramonensis with a new species, D.
lueriana (Pleurothallidinae). Annalen des Naturhistori-
schen Museums in Wien, B, 113, 119–132.
Karremans, A. P. (2016). Genera Pleurothallidinarum: an
updated phylogenetic overview of Pleurothallidinae.
Lankesteriana, 16(2), 219–241.
Karremans, A. P. & Bogarín, D. B. (2013). Three new spe-
cies of Dracontia (Pleurothallidinae, Orchidaceae)
from Costa Rica. Systematic Botany, 38(2), 307–315.
Karremans, A. P. & Smith, C. M. (2012). A note on genus
Dracontia (Orchidaceae: Pleurothallidinae), with a new
species. Harvard Papers in Botany, 17(1), 13–17.
Karremans, A. P., Bakker, F. T., Pupulin, F., Solano-Gómez,
R. & Smulders, M. J. M. (2012). Phylogenetics of Stelis
and closely related genera (Orchidaceae: Pleurothal-
lidinae). Plant Systematics and Evolution, doi: 10.1007/
s00606-012-0712-7.
Luer, C. A. (1986). Systematics of the genus Pleurothallis
(Orchidaceae). Monographs in Systematic Botany from
the Missouri Botanical Garden, 20, 1–108.
Luer, C. A. (2000). Icones Pleurothallidinarum. XX. Sys-
tematics of Jostia, Andinia, Barbosella, Barbrodia,
Pleurothallis subgen. Antilla, subgen. Effusia, subgen.
Restrepioidia. Addenda to Lepanthes, Masdevallia,
Platystele, Pleurothallis, Restrepiopsis, Scaphosepal-
um, and Teagueia. Monographs in Systematic Botany
from the Missouri Botanical Garden, 79, 1–140.
Luer, C. A. (2004). Icones Pleurothallidinarum XXVI. Pleu-
rothallis subgenus Acianthera and three allied subgen-
era. A second century of new species of Stelis of Ecua-
dor. Epibator, Ophidion, Zootrophion. Monographs in
Systematic Botany from the Missouri Botanical Garden,
95, 1–265.
Pridgeon, A. M. & Chase, M. W. (2001). A phylogenetic re-
classication of Pleurothallidinae (Orchidaceae). Lind-
leyana, 16, 235–271.
Pridgeon, A.M., Solano, R. & Chase, M.W. (2001). Phyloge-
netic relationships in Pleurothallidinae (Orchidaceae):
combined evidence from nuclear and plastid DNA se-
quences. American Journal of Botany, 88, 2286–2308.
Figure 8. Inorescence of S. platystylis with an open ower.
Photograph by A. Karremans based on Bogarín 5193
(JBL-Spirit).
LANKESTERIANA 17(2). 2017. © Universidad de Costa Rica, 2017.
202 LANKESTERIANA