Introductory discussion.2 Key to the subgenera of Pleurothallis.5 List of illustrations.8 Taxonomy of Pleurothallis.11 101 109 Index to scientific names.

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In the Pleurothallidinae three vegetatively similar genera are characterized by lepanthiform stems, i.e., secondary stems enclosed by a series of imbricating, ribbed, tubular sheaths dilated above to oblique ostia, and with the ribs and thickened margins of the ostia usually ciliate or scabrous. The three taxa may be differentiated from each other by the morphology of the column.The column of Lepanthes Sw. is wingless and footless, with a dorsal, apical or subapical anther, and an apical or ventral stigma. The short, hooded column of Lepanthopsis (Cogn.) Ames is Platystele-like, with the anther apical and the stigma transversely bilobed. The column of Pleurothallis R. Br. Sect. Lepanthiformes (Lindl.) Cogn., proposed here as Trichosalpinx, is usually elongated, more or less winged, with an apical, subapical or ventral anther and stigma, and with a foot usually well-developed. The column could be called Pleurothallis-like sensu lato. The relationship of Trichosalpinx to Pleurothallis is analogous to the relationship of Lepanthopsis to Platystele Schltr. If Lepanthopsis is to be maintained, this taxon should be elevated to the rank of genus. 54, No. 5 Etymology: From the Greek tricha (Tpvxa), ''a hair,' and salpinx (oadmvy §), '"'a trumpet," in reference to the ciliated ribs and margins of the trumpetlike sheaths of the secondary stems.Jesh Se ME Oe, @) (EL ag JN Vol.TYPE: Specklinia ciliaris Lindl.This somewhat diverse group of about 90 species is widely distributed from sea level to altitudes over 3000 meters, from southern Mexico to southern Brazil. Some species seem allied to Pleurothallis, others, to Lepanthopsis. The lips of some species are amazingly similar to the lips of some species of Pleurothallis sect. Specklinia, e.g. P. barbulata Lindl. and T. ciliaris, but vegetatively these two species are totally different. It would be interesting to discover if a common pollinator could account for this apparent example of convergent evolution.The following new combinations become necessary.

In the following new descriptions of species of Lepanthes, the sheaths of the secondary stems are referred to as '"'lepanthiform,'' a concept derived from the peculiar morphology of the sheaths typical for the genus. The secondary stems are enclosed by a series of tubular, ribbed, more or less imbricating sheaths with oblique, more or less dilated, margined ostia, and the ribs and margined ostia are grossly or microscopically ciliate or scabrous, occasionally glabrous. Lepanthiform stems are also found exclusively in Lepanthopsis (Cogn.) Ames and Trichosalpinx Luer.The flowers are described from the customary resupinate position, although the flowers are often looked upon by authors as non-resupinate. The position is purely arbitrary, depending upon from which perspective the flower is viewed on a pendent, horizontal, or erect rachis. When the flower reclines upon the leaf, either dorsally or ventrally, the lateral sepals are usually pointed toward the surface of the leaf, indicating a resupinate position, even though the leaf may stand erect, in which case the flower becomes nonresupinate if viewed from "'behind,"' Therefore, the unpaired middle sepal is described as dorsal in the following descriptions of new species. The dorsal sepal is three-veined unless stated otherwise; the lateral sepals are two-veined unless stated otherwise.The floral parts are often vividly multicolored, but these colors are not diagnostic. The colors vary greatly from population to population, and even among plants within a limited area. The colors given in the descriptions apply only to that particular plant. The degree of pubescence of the floral parts is also variable, depending upon the magnification. Even '"'glabrous"' parts become cellular pubescent under strong magnification.The petals are commonly transversely oblong or bilobed. The "'upper"' lobe is the lobe toward the dorsal sepal, the "'lower"' lobe is the lobe toward the lateral sepals. The ''length"' is the short distance from side to side; the "width" is the longer dimension from tip to tip.The lip of most species is so highly specialized that certain features require descriptive terminology for standardization of descriptions. In section Lepanthes, by far the largest, the lip is divided into two halves, or lobes, each of which consists of a blade, or lamina, borne by amore or less wedge-shaped, erect '"'connective.'' The united bases of these connectives form the ''body" with an anterior "'sinus,'' the angle of junction; posteriorly the body is connate to the under surface of the footless column. The free limbs of the connectives, one to either side of the column, carry the blades to parallel positions beside or above the column. The ''apex'' of the blade is the end nearer the anther, or toward the lateral sepals; the ''base'' of the blade is the end toward the dorsal sepal. The ''appendix,"' the extremely modified middle lobe of the lip, is a tiny organ, often intricately sculpted, somewhere on the under surface of the body of the joined connectives, or more often at t...

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