Cartago: Lankester 1066; Guanacaste: Standley & Valerio 44320, 
44426, 44465, 44608, 44724, 44849, 45140, 45314, 45658, 45977, 
46437; Limén: Standley 37540; San José: Alfaro 120 (in part). 
3. Isochilus linearis (Jacg.) R. Brown var. uni- 
lateralis (Robins.) Correll comb. nov. 
Tsochilus unilaterale Robinson in Proc. Amer. Acad. 
29 (1894) 323. 
Tsochilus linearis var. unilateralis has the largest flowers 
of any Isochilus. In this respect it approaches I. major. 
However, the few-flowered loose inflorescence, narrow 
leaves and verrucose leaf-sheaths place it closer to J. lin- 
earis. 'The flowers are as much as 1.5 cm. long and, in 
some of the specimens, are exserted above the leaves by 
the peduncle-like upper part of the stem. They are de- 
scribed by collectors as “‘pink’’, ‘*phlox-pink’’, ‘‘phlox- 
purple’ and ‘“‘rose-purple’’. The linear leaves are strictly 
erect or only slightly spreading. 
This variety is apparently restricted to a small region 
in east central Mexico where it is found on trees in 
humid forests from 500 to 1400 meters altitude. 
SPECIMENS EXAMINED: 
Mexico—San Luis Potosi: Pringle 5116 (Type of I.unilaterale), Nagel 
5106, Nagel § Juan G. 4796, Dino 6954; Tamaulipas: Viereck 953, 
Roszinsky 663; Puebla: Ostlund 5862. 
4. Isochilus major Chamisso & Schlechtendal in 
Linnaea 6 (1881) 60. 
’ Tsochilus latibracteatus A. Richard & Galeotti in 
Ann. Sci. Nat., ser. 8, 8 (1845) 22. 
Tsochilus chiriquensis Schlechter in Fedde Repert. 
Beih. 17 (1922) 25. 
This species typifies the second line of development 
found in Jsochilus. The comparatively large unilateral 
raceme and lanceolate leaves distinguish it at once from 
I. linearis and its varieties. The upper leaves which com- 
monly half conceal the inflorescence are nearly always 
[9 ] 
