Costa Rica, ““Bois 4 San Pedro de San Ramén. Epiphyte, de 7 
em. haut. Alt. 850 m. 27-VI-1925. Infl. pas plus longue que les 
feuilles.’’ 4.M.Brenes (96) 1301 (Type in Herb. Ames No. 44337) ; 
**Bosquet du Cerro de San Isidro de San Ramon. Alt. 1175 m. 10- 
VIT-1925.’" Brenes (151) 1334. 
Pleurothallis membraniflora (. Schweinfurth 
sp. nov. 
Herba nana, epiphytica, caespitosa. Radices fibrosae. 
Caules graciles, vaginis arctis tubularibus cum ostils cili- 
atis omnino obtecti. Folia obovata, in sicco coriacea, Mar- 
ginata. Racemi fasciculati, laxe pauciflori. Flores parvi, 
membranacel. Sepala dorso carinata. Sepalum dorsale 
oblongo-lanceolatum, trinervium. Sepala lateralia om- 
nino libera, anguste triangulari-lanceolata, leviter falcata, 
uninervia. Petala perparva, inconspicua, elliptico-ligulata. 
Labellum simplex, oblongum, apice basique late rotun- 
datum, trinervium. Columna late bialata. 
Plant dwart, caespitose, up to 4.8 cm. tall. Roots 
fibrous, numerous, glabrous, as stout as the stems. Stems 
slender, bearing one or more leaves, up to 5 em. long (an 
old stem), commonly 8.8 em. or less long, closely and 
entirely invested by usually four to seven tubular ner- 
vose-angulate minutely hispid sheaths which terminate 
in spreading ovate marginate ciliate mouths. Leaves ob- 
ovate, gradually narrowed to a shortly petioled base; 
lamina up to 9 mm. long, 4-5 mm. wide, marginate, 
minutely bilobed and apiculate at the rounded apex, e- 
rect, coriaceous, with the apical margins minutely carti- 
laginous-serrulate. Inflorescences fascicled at the apex of 
the stems and frequently also at several lower nodes of 
the stem, loosely up to 4-flowered. Flowers very small, 
membranaceous. Sepals parallel, about equally long. 
Dorsal sepal oblong-lanceolate, subacute, concave, about 
3mm. long and 1.5 mm. wide, 8-nerved through the 
lower half with the nerves prominently carinate on the 
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