G 
x The Orebid Review 3 
PZe VoL. XXVIII. Sept.-Ocroser, 19202 No. 333-334. a 
Ge ORCHIDS IN COSTA RICA. ES 
Ws C. H. LANKESTER. ?) 
OLITICAL Costa Rica forms very nearly a complete faunal and floral 
Poa. of its own, containing many endemic species. This, however, 
extends well down into the Republic of Panama, the orographic chain of 
Chiriqui having probably the same features, or but slightly modified, on the 
central volcanic range of mid Costa Rica. 
In the north-east the coastal forest belt, though divided from Nicaragua by 
the river San Juan, may be but slightly modified by it, yet that seems to be 
the northern limit of Cattleya Dowiana, which occurs sparingly in the 
vicinity of the Sarapiqui River, but has not, I believe, been found in 
Nicaragua, only a few miles away. Guanacaste, the north-western frontier 
province, is the extreme southern prolongation of the Sonoran type of 
vegetation, and this comes beyond its cantonal borders slightly south of. 
Puntarenas to the Rio Grande. Lower than this the forest belt changes 
more to the type of the majestic Atlantic forest, though it is not so thickly 
studded with trees, and has much lighter undergrowth, a fine feature being 
extensive areas of palms (Acanthorhiza?) on the flats, and on some of the 
foot hill slopes patches of Chamedorea nana. 
Orchids are less abruptly defined in their zonal distribution than are 
many other plants, the seeds being so admirably adapted for dispersal by 
high winds that frequently they are found in quite improbable situations. 
On the other hand, taking this fact into consideration, it is strange why 
some of them should be so very restricted in their range. In the moist 
regions of the middle zone they seem to be in a very great number of cases 
indifferently epiphytic or terrestrial; frequently they become the latter 
through accident, and at times form wonderful masses of growth in 
such situations as favour them. True terrestrials, on the other hand, very 
rarely occur as epiphytes ; Microstylis, possibly, may be an exception. At 
elevations of 5,000 to 9,000 ft. on the northern and north-eastern slopes. of 
the central volcanic range, a thick layer of humus accumulates on all lateral 
or horizontal branches of trees, and in this many Orchids, normally terres- 
trial, thrive luxuriantly among masses of Gesnerads, Bromeliace, 
Thibaudiz, Clusiz” epiphytic Melastomads, Ferns, Cyclantheras, 
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