78 ONCIDIUM. 



Oncidium seoratum is the type species of a group of Oncids 

 belonging to the section Microchila, characterised chiefly by the 

 elongated lateral sepals^ the dorsal one being almost orbicular, the 

 curiously crisped petals which often cling together when first open, 

 and by the dagger-shaped column wings. The grovip includes On. 

 trifurcatmn, Lindl.,* On. trUingue, Lindl.,t On. tetracopis, Rchb.^ 

 On. plagianthum, Echb.J On. cryptocopis, Echb., On. ludens, Rchb.J 

 On. lamelligerum, Rchb., On. monacMcum** Rchb., On. chrysodipterum, 

 nobis, and probably others, whose specific characters have not been 

 sufficiently defined to admit of their being technically distinguished 

 the one from the other. Till authentic materials can be brought 

 together for a more critical examination and comparison, it is 

 perhaps safest to leave them as they are, although they all bear so 

 strong a likeness to each other as to form a race of Oncids that 

 might be included under one species, the different forms representing 

 the different links in a chain of affinities too close to be rent asunder 

 by separate specific names. Moreover, the habitats of all occur within 

 a limited area on the Ecuadorean Andes, and most, if not all of 

 them have been imported with On. serratum. 



On. sessile. 



Pseudo-bulbs ovate-oblong, 3 — 4 inches long, much compressed, with 

 about three roimded ribs on each of the flattened sides, diphyllous. 

 Leaves ensiform, acute, 8 — 15 inches long, the whole plant of a pea- 

 green colour. Scapes 12 — 24 inches long, branched along the distal 

 half, the branches somewhat distant, alternate, spreading. Flowers 

 numerous, 1| inches in diameter, canary -yellow with the basal half of 

 the sepals and petals dotted with red-brown ; sepals and petals oblong, 

 obtuse, undidate, the dorsal sepal a little the broadest, the lateral 

 two spreadmg nearly parallel with the petals ; lip three-lobed, the side 

 lobes roimdish oblong, the front lobe larger, transversely oblong, deeply 

 emarginate ; crest sub-conic, oblate, tubercidose, wlute dotted with red. 

 Column wings narrow, denticulate. 



Oncidium sessile, Lindl. in Paxt. Fl. Gard. I. t. 21 (1851). Id. Fol. Orch. Oncid. 

 No. 174 (1855). Williams' Orch. Alb. V. t. 228. 



A native of Caracas and northern Colombia. It was first 



discovered on Santa Martha by Purdie, who sent it to the 



Duke of Northumberland, in w^hose gardens at Syon House it 



* Fol. Orch. Oncid. No. 4. t Paxt. Fl. Gard. II. t. 63. + Gard. Chron. 1873, p. 915. 



II Gard. Chron. 1873, p. 915. 



§ Id. XXIII. (1885), p. 756. ** Gard. Chron. XIX. (1883), p. 368, with fig. 



