A new species of Govenia (Orchidaceae) from Chiapas, Mexico Javier Garcia-Cruz and Victoria Sosa Garcia-Cruz, J. & V. Sosa1 (Departamento de Biología Evolutiva, Instituto de Ecología, A.C., Apartado Postal 63, 91000 Xalapa, Veracruz, México; e-mail: 1vic
[email protected]). A new species of Govenia (Orchidaceae) from Chiapas, México. Brittonia 58: 259–263. 2006.—Govenia rubellilabia, a new terrestrial orchid from Sierra Madre de Chiapas, Mexico, is described and illustrated. Diagnostic characters of this new species are compared with other species of Govenia. Govenia rubellilabia is similar in appearance to G. matudae, but it can be distinguished from this species by a shorter inflorescence with fewer flowers, greenyellowish tepals, a reddish lip lacking spots in the margin of the apex, and by a shorter anther beak. Key words: Chiapas, Govenia rubellilabia, G. matudae, G. praecox, Mexico, morphology, Orchidaceae, pollinia.
Govenia Lindl. is a terrestrial genus of Orchidaceae, with deciduous plicate leaves and showy flowers. The genus is widely distributed in the American tropics and subtropics; however, the greatest diversity has been reported in Mexico and Central America. In Mexico, the genus is represented by twelve species, five of which are endemic. Govenia is taxonomically challenging due to its remarkably uniform vegetative morphology, and because floral structures are difficult to observe in herbarium specimens. Previous studies have recognized a variable number of species. For example, Correll (1947) only working with herbarium material recognized five species and three varieties, while Dressler (1965) and Greenwood (1981) observing both live plants and herbarium specimens, recognized six and eleven species respectively, limiting their studies to the Mexican species. Dressler (1965) and Greenwood (1981) have discovered a good number of diagnostic characters observed from living plants, such as presence of corm or rhizome, number of leaves, inflorescence larger or shorter than leaves, general color of flowers, bars or spots on the abaxial and adaxial surface of petals and sepals, and number and disposition of spots on the lip. When doing field work for our ongoing project on the phylogeny and systematics of
Govenia (Garcia-Cruz and Sosa, unpubl. data), we collected some plants in Chiapas, Mexico, that corresponds to a new species. A complete taxonomic description as well as data on pollinarium morphology is presented. Morphological characters are also compared to other species of Govenia. New Species Govenia rubellilabia Garcia-Cruz, sp. nov. Type: MEXICO. Chiapas; Municipio de Motozintla, ca. 10–11 km sobre el camino Motozintla a Niquivil, encinar, ca. 2,200 m, 23 Jul 2004, J. Garcia-Cruz & O. Hernández 1446 (holotype: XAL!).(Figs. 1, 2A, C) Herba perennis. Inflorescentia racemosa laxa pauciflora; bractea floralis ovarii dimidium aequans. Flores parvi; sepala petalaque ex rubello viridi-luteola; labelli pagina adaxialis rubella, pagina abaxialis albida. Sepalum dorsale ellipticum usque oblanceolatum obtusum; sepala lateralia subelliptica subfalcata. Petala elliptica subfalcata. Labellum ovato-ellipticum, base cordatum, apice rotundatum, margine integrum.
Plants perennial terrestrial, deciduous, 30– 35 cm high. Corms subglobose. Sheathing bracts 3–4, originating from the basal nodes of the corm, tubular, successively larger upwards, apex obtuse, margin entire. Leaves 2, petiolate, articulate, blades ascending-
Brittonia, 58(3), 2006, pp. 259–263. © 2006, by The New York Botanical Garden Press, Bronx, NY 10458-5126 U.S.A.
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Fig. 1. Govenia rubellilabia. A. Flower in frontal view. B. Flower in ³⁄₄ view. C. Capsule. D. Habit. E. Column and pedicellate ovary, lateral view. F. Floral dissection. (From the holotype.)
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Fig. 2. Scanning electron photomicrographs of anther and pollinia from live material of Govenia rubellilabia (A, C) and Govenia matudae (B, D). A. Scale = 100 !m. B. Scale = 200 !m. C, D. Scale = 10 !m.
arcuate, plicate, elliptic to obovate, up to 26 cm long, ca. 8 cm wide, margin entire to obscurely undulate, apex sharply acuminate. Inflorescence 30–35 cm long including the stalk, originating from an upper internode of the corm, erect, with a solitary, narrow, tubular, scarious-membranous bract ca. 1 cm long, racemose, with about 8–13 flowers, the portion of the inflorescence bearing flowers approximately 10 cm from middle to apex; floral bract sessile, about half as long as the ovary triangular in outline, apex acute, 1.2– 1.4 cm long, ca. 3 mm wide, margin entire, greenish and membranous when fresh, when dried scarious-membranous, brown. Flowers ascending, 1.5–2 cm high, showy, sepals and petals green-yellowish, dorsal sepal and petals in both surfaces with shades of red, the lateral sepals tinged with reddish in the adaxial surface, the adaxial surface of lip reddish, the abaxial face whitish, lacking marginal apical spots. Pedicellate ovary ascending, straight to slightly arcuate, 1–1.5 cm long, ca. 1 mm diameter. Dorsal sepal in an angle of 70° to pedicellate ovary axis, smoothly ar-
cuate, forming a hood with the petals, slightly concave in the apical half, flat in the basal half, elliptic to oblanceolate when flattened, apex obtuse, mucronate, 11–14 mm long, 3–4 mm wide near the apex, margin entire, 5-veined. Lateral sepals arising from the lower margin of the column foot, spreading from the column axis, overlapping at the base, the apices close together, sometimes overlapping, when flattened subelliptical, smoothly falcate, apex acute, 8–10 mm long, 3–4 mm wide, margin entire, 5-veined. Petals arising from the lateral margins of the column foot, arcuate under the dorsal sepal forming a loose hood over the column, adjacent margins overlapping from the base to above the middle, elliptic when flattened, slightly falcate, apex acute, 9–11 mm long, 4–5 mm wide, margin entire, 7-veined. Lip forming a short, flexible claw at the base of the column foot, the apical half abruptly decurved, widely concave transversely nearly to the apex, broadly ovate-elliptic when flattened, the base cordate, apex rounded, 5–6 mm long, 4 mm wide, margin entire. Column
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Table I Diagnostic morphological characters of the new species of Govenia and related taxa
Species
Inflorescence length (cm)
Flower number
Flower size (mm)
G. rubellilabia
30–35
8–13
15–20
G. matudae
32–57
20–40
12–14
G. praecox.
20–35
10–40
15–25
G. superba
40–80
20–50
25–30
G. greenwoodii
45–80
25–40
22–25
G. viaria
30–70
20–30
20–25
G. dressleriana
70–90
30–50
25–30
Flower color
Lip color
green-yellowish, tinged with red yellowish tinged with orange-reddish yellow, flushed with red
reddish, abaxial face whitish brown with darker veins
greenish-yellowish, with transversely purple lines butter yellow, with transversely purple lines pale yellow, flushed or barred with red brown warm brown to greenish brown
yellowish
ascending, in an angle of 45° to the pedicellate ovary axis, then arcuate, ventral side deeply rounded, canaliculated in its entire length, the lateral margins above the middle forming a pair of vertical, widely rounded wings, about half as long as the column, column 6 mm long, 1.5–2 mm wide across the wings, whitish, with a few reddish, irregular lines or dots abaxially near the column foot, column foot deeply canaliculate, the thick walls of the channel continuous with the sharp sides of the column which above become the wings, 2–3 mm long, ca. 2 mm wide. Anther prominent, subconical, unilocular, 0.7 × 0.9 mm, with a short truncate beak at the apex, 149 !m long. Pollinia 4, in two pairs, in each pair the pollinia unequal, subellipsoidal, somewhat dorsiventrally compressed, 354 × 248 !m, sculpture lacunose. Distribution and Ecology.—The species has only been reported for the type locality in the Sierra Madre of Chiapas. Plants were found growing on rich organic soil in the transition between an oak forest and an evergreen forest at 2,200 m elevation. About 40
pale yellow
Lip marginal apical spots
Anther beak (µm)
absent
149, truncated
three reddish brown
760, rounded
3–5, dark warm brown many, pale reddish
672, obtuse 313, obtuse
cream yellowish
many purple
not observed
red-brown
5 brown
451, emarginated
pale purplish reddish brown
3–4, yellow to brown
1064, rounded
individuals were observed in the population, forming a clump. Phenology.—Flowering occurs from June to July. Etymology.—The specific epithet makes reference to the color of the lip (Latin rubellus = reddish and labia = lip). Govenia rubellilabia differs considerably from other species of the genus although it resembles G. matudae E.W.Greenw. & Soto Arenas, which was collected in the same area. Both species grow sympatrically and flower simultaneously. The two species have similar flower size, reddish sepals and petals, and labella with an ovate-elliptic outline. However, G. matudae has a larger raceme, from 11cm to 19 cm long (vs. 10 cm long in the new species), with 20–40 flowers (vs. 8–13 in G. rubellilabia), and its tepals are yellowish, while the lip is basically brown with 3 reddish brown spots in the apex margin (vs. greenyellowish tepals, lip reddish without spots in the apex margin in the new species). Anther and pollinia sculpturing of this species also show differences (Fig. 2). The beak of the an-
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ther of G. matudae is larger than that of G. rubellilabia, and the pollinia sculpture in G. matudae is foveate, whereas in G. rubellilabia it is clearly lacunose (Fig. 2). Other species of Govenia with small flowers include Govenia praecox Salazar & E.W.Greenw. and G. viaria Dressler, which are characterized by a large dense racemes from 6–20 cm long, with 10–40 yellow flowers. In G. praecox the flowers are flushed with red, and the lip is pale brown with 3–5 dark brown spots in the marginal apex, whereas in G. viaria the flowers are flushed with red-brown, and the lip is red-brown with 5 brown spots in the apex margin. The rest of the yellow flowered species (G. superba (Lex.) Lodd., G. greenwoodii Dressler & Soto Arenas, and G. dressleriana E.W. Greenw.) are characterized by dense racemes and larger flowers. Table I summarizes differences between G. rubellilabia and these taxa.
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Acknowledgments We thank J. Rzedowski for writing the Latin diagnosis and F. Lorea for his useful comments on a previous version of the manuscript. We are grateful to Edmundo Saavedra for the illustration and to Olivia Hernández for her help in the field. Bianca Delfosse edited the English version of the manuscript. This research was fully supported by a CONACyT graduate scholarship to J. G-C and a scholarship and a research project directed by VS (CONACYT 39601). Literature Cited Correll, D. S. 1947. Some revisions of American orchids. IV Revision of the Genus Govenia. Lloydia 10: 218–228. Dressler, R. L. 1965. Notes on the genus Govenia in Mexico (Orchidaceae). Brittonia 17: 266–277. Greenwood, E. W. 1981. Govenia in Mexico, an introductory note. Orquidea (Mexico City) 8: 114–120.
