s 



^, 



Tribe^BPIDBNDRB^. 



SUB- TRIBE PLEUROTHA LLE^. 



GcBspitose herbs, ivith slender stems that are not pse^ido-bvlboiis, niono- 

 phyllous and terminated by a one- or many-flowered inforesceiice. 



PLEUROTHALLIS. 



R. Brown in Alton's Hort. Kew. ed. II. p. 211 (1813). Lindl. Gen. et Sp. Orch. p. 4 (1830). 

 Benth. et Hook. Gen. Plant. III. p. 488 (1883). 



Althougli Pleurothallis is one of tlie largest genera in the orchidean 



family, it has hitherto been thought of so little interest to cultivators that 



it has been passed over in silence by the compilers of every horticultural 



work on orchids with which we are acquainted, with the exception 



of Mr. E. S. Rand, who cursorily meutions it.* It has, however, a 



certain scientific importance as the typical genus around which other 



genera are grouped, forming the sub-tribe Pleurothallece, of which the 



most distinctive common characters are given above. This sub-tribe 



includes in the aggregate, according to Mr. Bentham^s estimate, over 



650 species, to which additions are frequently being made by new 



discoveries, so that this one sub-division contains probably more than 



one-tenth of the whole of the Orchideas ; the species are very unequally 



divided among ten genera, t some of whose names even are practically 



unknown to horticulture. 



Upwards of 350 species of Pleurothallis are known to science, 



all natives of the mountains of tropical America, at a considerable 



elevation. They occur on the Andes from Bolivia to Mexico, ascending 



to 10,000 — 12,500 feet towards the southern limit of their range; they 



are also found on the mountains of Brazil and in the West Indies. 



Although upwards of 100 of the species have at difierent times been 



* Orchids, a description of the species and varieties grown at Glen Ridge, near Boston, 

 U.S.A., p. 375. 



t Thus, Pleurothallis 350, Stelis 150, Physosiphon 4, Lepanthos 40, Restrepla 20, Brachio- 

 nldlum 3, Masdevallla 100, Arpophyllum 6, Octonieria 10, ]\Ieiracyllium 3 ; all natives of 

 tropical America, from southern Brazil to central Mexico, most of them alpine. 



