Tab. 7189. 



PLEUROTHALLIS immersa. 



Native of New Grenada. 



Nat. Ord. Orchide.e. — Tribe Epidendre.e. 

 Genua Plettrothallis, B. Br. ; (Benth. et Hook.f. Gen. PI. vol. iii. p. 488.) 



Pletjkothallis (Elongate) immersa ; caudice repente, caulibus brevibus 

 vaginitis, foliis oblanceolatis subacutis breviter petiolatis, Rcapo solitario 

 gracili folio longiore basi sulco medio folii abscondito, vaginis paucis bre- 

 vibus appressis acutis, racerno elongato nutante multifloro, floribus 

 secundis penduhs fusco-purpureis, bracteis parvis lanceolatis, sepalis 

 rectis hnean-oblongis dorso alte cariuatis intus pubescentibns, lateralibus 

 ■ in lammam doreali ffiquilongam sed paullo latiorem apice bideutatam 

 coalitis petalis parvis columns aaquilongis spadellreforraibus obtusis, 

 labello oblongo obtuso recurvo granulato, carinis 2 crassis la3vibus percurso. 



P. immersa, Lindl. et Reiehb.f. in Bonplandia, vol. iii. p. 223 ; in Walp Ann 

 Bot vol. vi. p. 177; Lindl. Fol. Orchid. PhurotJiall. p. 38, «. 236' •' Rolfe 

 in Gard. Chron. 1889, vol. i. p. 74. ■* 



The division of the immense genus Pleurothallis (it 

 contains upwards of 350 species) into natural groups 

 characterized by limitable characters presents great diffi- 

 culties, and the labours of Lindley, Reichenbach, and 

 Bentham in this direction are not harmonious. Thus 

 Reichenbach, in Walper's Annals, refers P. immersa to a 

 group of which the type is PL chamensls, but as he has 

 some thirty or forty of such types, and gives no charac- 

 ters for his types, nothing definite is gained thereby. 

 He further says that P. immersa is allied to P. bicarinata, 

 a species that nowhere appears in his enumeration ; it is 

 however figured in this work (t. 4142) and shows no very 

 close affinity with P. immersa, except in that the sepals 

 are keeled at the back. Lindley in his " Folia Orchidacea," 

 places P. immersa in the group Apodce Ccvspitosw, with 

 which as that group is defined by both himself and 

 Bentham it appears to me to be altogether at variance ; 

 the Apodce being minute tufted species of altogether 

 different habit. According to Bentham's grouping of the 

 species (in Gen. Plant.) it falls naturally into his first 

 division of Elongates floribvndce, having an elongate many- 



Auoust 1st, 1891. 



