68 



circumscribed. The genera properly belonging to Pleu ro- 

 th allidte are, Plcurothallis, Stelis, Leparithes, Ociomeria, 

 Stenoglossum, Restrepia, Phi/sosiphon, and Masdevallia ; to 

 which must be added Myoxanthus and Specklinia, if those 

 vo genera can be retained. But the former I have formerly 

 educed to Pleurothallis, and a more extensive knowledge of 

 the species has led me to adopt the same conclusion respect- 

 ing Specklinia, which is only characterized by an extension 

 of the base of the lateral sepals, in which particular there are 

 so many insensible gradations that it cannot be practically 

 employed ; all the species of Pleurothallis are more or less 

 gibbous at the base of the lateral sepals. 



Among these genera Pleurothallis is by far the most ex- 

 tensive, comprising species with considerable difference in 

 habit, and in the subordinate details of their fructification. 

 As the latter do not appear to be in any way connected with 

 the former, it seems desirable to employ for natural purposes 

 the habit alone, which furnishes some well marked distinc- 

 tions. Some of the species have long spikes of flowers, 

 considerably extending beyond the foliage ; these form one 

 section. Others have the spikes visibly shorter than the 

 foliage, and form a second section. A third consists of those 

 whose flowers are arranged in a fascicle at the base of the 

 leaf, and not in spikes. Finally, a fourth section consists of 

 small species with solitary or nearly solitary flowers growing 

 on long capillary peduncles. 



Taking this mode of distribution, the species may be con- 

 venientlv arrano^ed as follows. 



Section I. Elongate. Spica^ v. racemi foliis evidenter 

 longiores, v. omnino a^quales. 



* liaccmosco ; nempe pedicellis quam bractese evidenter 



longioribus. 



t Disepalse (nempe sepalis lateralibus fere ad apicem 

 connatis) ; labello indiviso. 



1. P. Mattheivsii (Lindl. in Comp. Bot. Mag. v. 2. Acronia phalangifera, 



Presl. Synib. t. .5/.) ; folio oblongo acuminato basi rotnndato racemis 

 breviore caule longiore, sepaUs petalisque sequilongis setaceo-acuminatis, 

 labello transverse obtusissimo medio carnoso cordato Baargine dilatato 

 membranaceo. Peru. 



2. P. liestrepioides ; folio oblongo coriaceo subsessili spicis subgeminis strictis 



duplo breviore, floribus ringentibus disepalis glabris longe pedunculatis, 

 sepalis ovatis acuminatis inferiore cymbiformi bidentato, petalis confor- 



