THE IDENTITY OF SOBRALIA LEUCOXANTHA, WITH THREE NEW SPECIES, TWO CLOSELY ALLIED AND ONE MORE DISTANT Robert L. Dressler' * and Franco Pupulin 2 * Abstract: Sobralia blancoi and S. pendula are both close allies of S. leucoxantha. We also descri be S. aspera, a species that appea rs to be more distantly all ied Key words: Orchidaceae, Sobralia, leucoxantha, blancoi, aspera, pendula, Costa Rica, Colombia. Introduction: The name Sobralia leucoxantha properly belongs to a species w ith slender shoots and med ium-sized white flowers, w ith some ye ll ow within and 2 purple blotches basally in the throat. The ventral outline of the lip is marked ly convex in lateral view, and flowering is not tightly coordinated (or gregari ous). Further, S. leucoxantha and two of the species to be descri bed here often have inflorescences born e on leafless stems that are usually shorter than the leafy stems. Sobralia pendula has about five low, rounded keels on the li p, w hile S. leucoxantha and S. blancoi lack kee ls; S. blancoi is quite distinct in its coloration, and also has a strong, distinctive perfume. Sobralia aspera does not bear inflorescences on leafless stems, its fl owering is gregarious, and the flowers last only a few hours, as in the majority of Sobralia Section Abbreviatae. Sobralia leucoxantha was descri bed by Reichenbach in 1866, w ith a brief but fa irly clear description. Unfortunately, the name S. leucoxantha w as later applied to a quite different species (Curtis' Botanica l M agazine, plate 7058, 1889, possibly = S. chrysostoma Dressler), and came to be appli ed quite indiscriminately to every medium to large white-flowered species in Central Ameri ca except S. macrophylla Rchb.f. (Dressler, 2001; Dressler & Boga rfn, 2007). When study of the * Jardin Botanico Lankester, Universidad de Costa Rica, Apdo. 1031-7050, Cartago, Costa Rica, A.c. Centro de Investigaci6n en Orquideas de los Andes, Universidad Alfredo Perez Guerrero, Extensi6 n Gualaceo, Ecuador. Author for correspondence: rdress le@cari ari.ucr.ac. cr. Author for correspondence: fpupulin @ca riari.ucr.ac.c r. 152 ORQUIDEOLoc ia XXV(2), 2008
type specimen showed s. leucoxantha to be a distinct species, some authors took up the name s. powellii Schltr. (based on a species known only from low-land, ce ntral Panama) as a catchall name for white-flowered species of Ce ntral America, and even Colombia and Ecuador. The authentic S. leucoxantha is a slender plant with medium-sized flowers (Reichenbach compared them to those of s. fenzliana) (fig. 1), with a purple spot within on each side near the base of the throat. The buds and lip are markedly convex ventrally, and the inflorescences are frequently borne on leafless stems (fig. 2-3). While most Sobralia flowers are so ephemeral that they well merit the Costa Rican name "flor de un dra," the flowers of s. leucoxantha and its closest allies are delicate but last for about three days. These species are somewhat seasonal, but their flowering is not tightly coordinated (gregarious, or with simultaneous flowering in a species in a region), as in most other species of the Section Abbreviatae Brieger. Plants of this or very similar species are frequent in Costa Rica and western Panama (fig. 4-6), but records from other countries are doubtful. M ost of the Panamanian materi al that we have seen represents other species, but S. leucoxantha has been found in Costa Rica near the Panamanian border and flowers photographed south of Lago Fortuna, in ChiriqUI, Panama, appear to be s. leucoxantha, though the purple spots typical of Costa Rican materi al are not visible in the photos. In addition to the three closely allied species treated here, there are other slender plants superficially similar to s. leucoxantha that have somewhat wider inflorescences (i n proportion to length) and white flowers with yellow within, but these show typical gregarious flowering and the flowers last only a few hours. Such plants occur widely in Costa Rica and western Panama, but we are unsure, at this time, how many species are involved. We here describe one of the most distinct as a new species. The status of other similar populations requires further study. In s. leucoxantha and its closest allies, the developing inflorescence is usually quite distinctive (fig. 7). It is long and slender and only slightly thickened in its ea rly stages, the developing inflorescence is often subtended and partially covered by a narrow, short-lived, plicate, foliar bract that is narrower than the foliage leaves and may dry before flowering. Sobralia leucoxantha and two of the other species treated here frequently bear inflorescences on quite leafl ess ste ms. In such stems, usually shorter than the leafy stems, there mayor may not be a narrow, plicate, subtending foliar bract. In the past, some specimens of the s. leucoxantha complex have been identified as s. maera Schltr, a later name. Garay (1978, under s. powellii) states that s. maera is not a synonym of s. leucoxantha, and Hamer (1974) used the name s. maera for what may be s. wilsoniana Rolfe, a poorly known species that may have been confused with S. m aerantha in herbaria. However, study of Schlechter's description, and his sketches of the habit and fl ower parts and of the original ORQUIDEOlOCIA XXV(2), 2008 153
specimen (Brenes 295), at AMES, suggest that s. macra was, indeed, a small plant of s. leucoxantha. All of the measurements given by Schlechter fall within the range of s. leucoxantha, and most are much too small to be s. wilsoniana. Still, plants from the type locality may well show distinctive features not mentioned in Schlechter's description. Sobralia leucoxantha, especially, varies greatly in size. We found a plant about 2.5 meters tall, with proportionately large leaves and flowers, at Monte Sky, near Purisfi, Cartago, Costa Ri ca (fig. 8). A description of the plant as a new species was prepared, but this idea was quickly abandoned when we found a division of the sa me plant growing in the Lankester Botanical Garden and staying within the usual measurements of S. leucoxantha. There is considerable variation is both size and form within S. leucoxantha, as used here. Further study may show that we are sti ll treating more than one species under that name. Here, We offer a key to the three species of the leucoxantha complex, in the stri ct sense, as we now understa nd it. That is, those species with irregular (not gregarious) fl owering, flowers lasti ng about three days, and often with inflorescences borne on leafless stems. KEY TO THE SPECIES OF THE SOBRALIA LfUCOXANTHA COMPLEX 1. Lip with low, rounded keels within, throat yellow marked with brown; lamina of lip so mewhat lilac...... S. pendula 1. Lip without keels............ 2 2. Flowers white with yellow and 2 basal purple blotches within throat; column 2.3-3.3 cm long... S. leucoxantha 2. Lip with a dark purple "mask" on lilac background; column 2-2.4 cm long; with a strong, distinctive perfume..... S. blancoi SOBRALIA LfUCOXANTHA Rchb.f., Beitr. Orchid.-K. C. Amer. 68 (1866). Holotipo: Costa Rica, Wendland 1246 (W-R!). Sobralia m acra Schltr., Repert. Spec. Nov. Beih. 19: 161 (1923). 154 ORQUIDEOLOGIA XXV(2), 2008
Terrestrial or epiphytic, roots 0.15-1.2 cm in diameter; stems 30-2 50 cm, 3-5 mm in basal diameter; leaves on upper stem, 17-36 x 2-5 cm, lanceolate, acuminate, w ith 9 prominent vei ns beneath, including marginals; sheaths green with network of scurfy brown; bract cluster 5-9 x 0.5-0.7 cm, ellipsoid, usually subtended by a plicate, foliar bract 2.8-3 cm wide, outer inflorescence bracts 8-8.5 x 0.7-1.1 cm, enrolled; flowers white, yellow within, with 2 lateral, basal purple blotches in throat; ovary subsessile, 1.5-2.4 cm; sepaline tube 0.7-1.3 cm; dorsal sepal 3.2-5.7 x 1.1-2.1 cm, obovate-oblong or elliptic-obovate, apiculate, lateral sepals 4.1-6.8 x 1.2-1.9 cm, oblong-obovate or ovate-oblong, apiculate; petals 3.9-5.8 x 1-2.2 cm, elliptic, abruptly subacute; lip 5-7.6 x 3.1-5.9 cm, subcuneate, obovate, basal ridges 0.6-1.4 mm long, well separated, lip w ithout keels; column 2.2-2.9 cm long, basally very narrow, distally 3-6.5 mm dorsoventrally, 4-6.5 mm wide, arms ascending, column swollen beneath; capsule 10-1 3.5 x 1.5-2 cm. Fig. 9. SOBRALIA BlANCOI Dressler & Pupulin, Orquideologfa 25(2): 139. 2008. Holotype and distribution: Costa Rica: Alaj uela, Reserva Alberto Brenes; cultivated in the Lankester Botanical Garden, Accession 05922, pressed from cult. 1 April 2006, R. L. Dress ler 6706 (CR). Botanical description: Roots 3-5 mm in diameter; stems 40-62 cm, ca. 3 mm in diameter basally; leaves 15-1 9 x 2.7-4.3 cm, ovate or elliptic-ovate, acuminate, major veins 9; bract-cluster of inflorescence ca. 5 x 0.6 cm., narrowly lanceolate in outline; sepals and petals white or cream, blade of lip dark purple, with pale pink or lilac basally and distally, with 2 yellow streaks ventrally within; ovary subsessil e, 1.2-1.7 cm; sepaline tube 1-1.5 cm; dorsal sepal 4-6.2 x 1.3-2 cm, elliptic-oblanceolate, acuminate; lateral sepals 4.4-6.5 x 1.7-2.3 cm, ellipticoblong, acuminate; petals 4.2-5.8 x 1.8-2.4 cm, elliptic-oblanceolate, subacute; lip 4.6-6.8 x 3.3-5.4 cm, obovate, deeply convex basally, basal ridges ca. 4-8 mm, with floor of lip descending abruptly near apices of ridges; column 2.1-2.5 cm, apically 3-5 mm wide, 4 mm tall, arms 2-3 x 1-1.6 mm, falcate, reaching near upper surface, tightly apressed to rest of column; column with 2 prominent keels ca. 8 mm long below stigma, basally very narrow. Fig. 10-11. Paratype: Same plant as holotype; pressed 30 June 2006, R. L. Dressler 6784 (USJ). Etymology: The epithet of this attractive species honors M ari o Blanco Coto, one of the most promising young orchid botanists of Latin America at this time, who has apparently prepared material of this species. ORQUIDEOLOGIA XXV(2), 2008 155
Taxonomical comments: When we first saw this species, in Monteverde, we thought it to be a color variant of S. leucoxantha, but we have now seen several plants both from Monteverde and from the area of San Ramon, and we believe it to be a distinct species, with the base of the lip strongly laterally flattened, and with a strong and very distinctive perfume. Further, the basal ridges are small, and the ventral surface of the lip bends downward immediately distal to the basal ridges. In all cases, the lip is dark purple with pale lilac or pink basally and distally, so that there is a band of darker purple across the blade, and the flower appears to have a dark mask. SOBR4llA PENDULA Dressler & Pupulin, Orquideologfa 25(2): 140. 2008. Holotype: Costa Rica. Cartago: Turrialba, Santa Cruz, Las Abras. Frente al Rio Cano Seco, en arboles solitarios en un potrero, justo antes de la Finca de Ema Quesada Chinchilla. Bosque nuboso de las faldas del Volc1n Turrialba, ca. 2000 m.; Cultivated in the Lankester Botanica l Garden, Accession 12985; flowered in cultivation 31 March, 2006, Dressler 6746 (CR), with flowers in alcohol (JBL). Botanical description: Plant epiphytic, roots to ca. 8 mm in diameter, leafy stems 50-60 cm long, 2-3 mm in basa l diameter; sheaths sulcate, verruculose, younger stems and sheaths sparsely scurfy, leaves 16-19 x 1.8-3.8 cm, ovatelanceolate, acuminate, with 9 keels beneath, including marginals; inflorescence usually from leafless stems 18-32 cm long, bract clusters 6-6.5 x 0.5-0.6 cm; buds sometimes basally green and distally brownish, flowers subpendent, sepals greenish cream or pale pink without; petals greenish cream, apices somewhat rose-purple; lip cream, throat dark brown within with yellow stripes, then yellow and then white distally, margin light rose-purple, undulate; ovary subsessile, 1.2-4.2 cm; sepaline tube 1-1.5 cm; dorsal sepal 5.1-5.6 x 1.6-1.7 cm, elliptic-oblong, obtuse, acuminate, lateral sepals 5.1-6 x 1.6-2 cm, oblong or lance-oblong, apiculate; petals 4.3-5.1 x 1.6-1.7, oblanceolate-elliptic, obtuse, apiculate; lip 5.5-6.6 x 4-5.2 cm, cuneate, obovate, bilobed apically, basal ridges 0.9-1.2 cm, basahy united, with 3-5 low, rounded keels; column 3.2-3.7 cm, distally ca. 8 mm wide, 6 mm dorsoventrally, column arms 5-6 mm, falcate, curving upward. Fig. 12-13. Paratypes: Costa Rica: Alajuela, area of Monteverde, from Alvaro Salazar, 1600 m, 10 20' 441 "N, 84 48'585"W, JBL liquid; Cartago, Guarco de Tejar, Finca de Socorro Gonzalez, pressed from cult. R. L. Dressler 6665 (CR); same, pressed from cult. 30 May 2006, Dressler 6744 (USJ); Cangreja de Casa Mata, de Daniel Jimenez, JBL liquid. We have a Panamanian plant of this species, but it's exact origin is unknown. Other Panamanian plants, of known origin, will probably prove to be this species. 156 ORQUIDEOlOGIA XXV(2), 2008
Etymology: The epithet is based on the Latin pendulus, or pendent, referring to the usual position of the flower. Taxonomical comments: Though clearly related to S. leucoxantha, this species has a relatively large flower with three to five low, rounded keels within the lip, the bud and the lip are less convex ventrally, and the buds may be somewhat green basally and brown distally. The undulate, rose-purple margins of the lip, and its relatively large size make this a very attractive flower. In cu ltivation most of the flowers are self-pollinated. Some of the inflorescences produce only one flower, and the length of the ovary at anthesis varies remarkably, both features that may be related to autogamy. SOBRAlJA ASPERA Dressler & Pupulin, Orquideologfa 25(2): 748. 2008. Holotype: Costa Rica. Cartago: above Pacayitas, ridge-top forest; cu ltivated in the Lankester Botanical Garden, Accession 14700; pressed from cult. 21 June 2006 Dressler 6783 (CR). Botanical description: Plant terrestrial or epiphytic, roots to 5 mm in diameter; stems 50-85 cm, 3 mm in basal diameter; leaves on upper ste m, 17-25 x 2.5--3.5 cm, lanceolate, acuminate, with 9 prominent veins beneath, including marginals; sheaths blackish, surface roughened; bract cluster ca. 4.5 x 0.7 cm, ellipsoid, subtended by a plicate, foliar bract 2.8-3 cm wide, quite like the foliage leaves, outer inflorescence bracts 8-8.5 x 0.7-1.1 cm, enrolled; flowers white with yellow in throat; ovary subsessile, 1.2-1.5 cm; sepaline tube 1.1-1.3 cm; dorsal sepal, 4.1-4.3 x 1.1 cm, elliptic, apiculate, lateral sepals 4.1-4.5 x 1.1-1.2 cm, elliptic, apiculate; ~etals 4.1 x 1.1-1.2 cm, elliptic-oblong, abruptly subacute; lip 4.1-5 x 2.9-3.1 cm, subcuneate, obovate, basal ridges 6-7 mm long, well separated, lip without keels (but the lamina is somewhat corrugated in the throat), basally scurfy within, shallowly convex beneath; margin of lip distally undulate; column 2.1-2.2 cm long, basally very narrow, distally 3 mm dorsoventrally, 4 mm wide, arms ascending-porrect, reaching above apex of column, column somewhat swollen beneath. Fig. 14-15. Etymology: The epithet is based on the Latin asper or rough, referring to the nearly black, rough surface of the leaf sheaths in plants collected in the wild. In cultivated plants, the rough, blackish crust does not develop on the newer leaf sheaths. Taxonomical comments: Sobralia aspera resembles s. pendula in the markedly undulate lip margins, but the flower is smaller and more horizontal, and, like ORQUIDEOLOCIA XXV(2), 2008 157
5. leucoxantha, the column is small and slender and the lip lacks keels, though the floor of the lip is somewhat corrugated. The column has prominent, rather porrect arms. In the field, the leaf sheaths of this species are dark and somewhat roughened, and the inflorescence is consistently subtended by a well-developed, plicate, persistent foliar bract. We have not seen any inflorescence of this species on leafless stems, as is frequent in the other species treated here. Plants similar to this species but without the dark, asperate sheaths are known in northwestern Costa Rica and in western Panama. All of these plants have ellipsoid inflorescences a bit wider (in proportion) than is usual in 5. leucoxantha. Until more flowering material is available, these other populations should remain nameless. Here, We offer a key to the three species of the leucoxantha complex, in the strict sense, as we now understand it. That is, those species with irregular (not gregarious) flowering, flowers lasting about three days, and often with inflorescences borne on leafless stems. KEY TO SPECIES OF THE SOBRALIA LEUCOXANTHA COMPLEX 1. Lip with low, rounded keels within, throat yellow marked with brown; lamina of lip somewhat lilac... :... 5. pendula 1. Lip without keels......... 2 2. Flowers white with yellow and 2 basal purple blotches within throat; column 2.3-3.3 cm long... 5. leucoxantha 2. Lip with a dark purple "mask" on lilac background; column 2-2.4 cm long; with a strong, distinctive perfume................ 5. blanco; Acknowledgments We wish to thank especially Diego Bogarfn, Daniel Jimenez, Pepe Moya, Alvaro Salazar and Socorro Gonzalez for information or plant materials, and we are grateful to the Costa Rican Ministery of Environment and Energy (MINAE) and its National System of Conservation Areas (SINAC) for issuing the scientific collecting permits 36702 and 36891, and the Scientific Passports 1092 and 1283, that authorized the collection of wild species treated in this paper. 158 ORQUIDEOlOGIA XXV(2), 2008