AN ALTOGETHER remarkable species of the genus Pleurothallis from the Republic of Honduras is described below. It is without close allies in Middle America and in the structure of the rostellum proves to be quite exceptional. In the bud the lamina formed by the coherent lateral sepals closely enfolds the labellum, but at anthesis becomes markedly convex, the lateral margins becoming almost contiguous. The labellum extends parallel to and in close contact with the convex sepaline lamina and is conspicuosly fringed with the segments of the fringe minutely glandulose. The column is characterized by an extraordinary development of the rostellum; this organ is deeply trifid with the elongated lateral segments linearoblong, more or less porrect near the base and sharply deflexed beyond the middle.

Pleurothallis oscitans Ames, sp. nov. Herba verisimiliter caespitosa. Caules secundarii elongati, graciles, monophylli, prope basim paucivaginati, vaginis tubularibus arcte adpressis. Folium coriaceum, oblongolanceolatum, acuminatum. Pedunculi fasciculati, ex axilla folii orientes, plus minusve septemflori, verisimiliter penduli. Flores atropurpurei. Sepala lateralia in laminam valde convexam cohaerentia, extus valde carinata, mar

gine longe ciliata, superne prope marginem longe glanduloso-hirsuta. Sepalum dorsale anguste lanceolatum, apiculatum, acutum, extus per medium carinatum, intus valde pilosum. Petala minuta, lanceolata, uninervia,acuta, margine fimbriata. Labellum anguste lanceolatum, acutum, superne dense papillosum, prope basim breviter bicarinatum, margine dense fimbriato. Columna alata,apice irregulariter dentata, rostello trifido permagno instructa.

Epiphytic herb. Roots coarsely fibrous, whitish, glabrous. Secondary stems monophyllous, 14-19 cm. long, slender, about 2 mm. in diameter when dry, with a closely appressed elongated tubular sheath near the base and with one or more short tubular scarious sheaths near the rhizome, but otherwise the secondary stems are naked and smooth. Leaf terminating the stem, 9-14.5 cm. long, about 2 cm. wide, coriaceous, oblong-lanceolate, acuminate, acute. Peduncles one to three, successive, in the axil of the leaf, issuing from a short spathe-like bract, ascending or strongly arcuate, 5-7 cm. long, each peduncle with a short tubular closely appressed sheath near the base. Raceme 5-6.5 cm. long, about 7-flowered, more or less curved or drooping. Bracts of the raceme tubular at base, acuminate, smooth, exceeding the pedicels. Flowers 10-12 mm. apart. Pedicel and ovary about 5 mm. long, obliquely ascending, smooth. Lateral sepals 12-13 mm. long, coherent throughout their length forming a strongly convex elliptical lamina 8 mm. wide, and conspicuously bicarinate on the outer surface with each carina decurrent on the ovary forming a conspicuous wing; sepaline lamina smooth on the outer surface, conspicuously glandular-hairy near the margin on the inner surface. Dorsal sepal up to 17 mm. long, about 3 mm. wide, narrowly lanceolate, apiculate-acute, carinate along the mid-rib on the outer surface with the carina decurrent on the ovary, glandular within and with long glandular

hairs along the margin. Petals about 3 mm. long, lanceolate, acuminate, 1-nerved, fimbriate on the margin with the segments of the fringe minutely glandulose. Labellum about 7 mm. long, narrowly lanceolate, closely appressed to the lateral sepals, shortly bicarinate at the base, glandulose on the upper surface with the margin fimbriate-dentate, with the slender segments minutely glandulose near their base. Column about 3 mm. long, produced into a short foot, conspicuously winged with the wings deeply lacerate-dentate; rostellum trifid, the lateral divisions porrect-pendent. Pollinia two.

REPUBLIC OF HONDURAS, Department of Cortes, Santa Cruz de Yojoa. Epiphyte in open mountain forest at 2,000 feet altitude. Flowers dark purple. August 26, 1933. J.B.Edwards 515. (TYPE in Herb. Ames No. 39597.)

EXPLANATION OF ILLUSTRATION

PLEUROTHALLIS OSCITANS Ames. Upper part of plant drawn natural size. 1, side-view of a flower. 2, a fragment of the margin of the labellum showing the glandulose segments. 3, labellum, column and petal viewed laterally. 4, labellum flattened to show the outline. 5, sepaline lamina formed by the union of the lateral sepals. 6, dorsal sepal. 7, column (anther removed to disclose the trifid rostellum) and petals. 8, pollinia united by the glutinous substance of the rostellum. 9, column (anther in situ).

Drawn by Blanche Ames, November 1933