392 A YEAR OF COSTA RICAN NATURAL HISTORY 



were so often of the same size and shape, and not ternate 

 in so many cases, that it was impossible to distinguish the 

 trees by the leaves alone. 



The river was reached most quickly from the house by a 

 path toward the east, which soon dropped into the steep- 

 sided ravine and led a beautiful course under guanacastes, 

 palms, wild cacaos, cecropias and bull's horn thorns, with 

 many other trees we did not recognize. Many begonias, 

 differing from those about Juan Viiias, were full of bloom, 

 draping the rocks and tree-trunks, and the path was often 

 ankle deep in ferns and selaginellas. At the bottom of the 

 trail was an especially wide and dense mat of vegetation, 

 mostly of a species of Selaginella strange to us, having more 

 pointed fronds than those we had seen. Many of the forest 

 trees had an abundance of aerial roots which formed net- 

 works outside of the trunk and between the buttress-like 

 ridges of the trunk where such ridges existed. As usual 

 there were numerous aroids in the undergrowth and not a 

 few in the form of vines climbing the tree-trunks. The 

 bright green of fresh new Heliconia leaves relieved the dark 

 green picture. One morning one of these, a fresh, young, 

 perfect leaf, was "smoking" conspicuously; the sun had just 

 begun to fall on it, and with such force that the leaf tran- 

 spired or lost water vapor as a visible mist some inches wide 

 and rising several feet above the leaf tip before it was lost 

 in the air. 



Termites' nests, high on tree-trunks, and with covered 

 trails leading up and down, were common. A typical forest 

 tree with a stem immensely tall before it branched, bore 

 a termites' nest at a height of more than forty feet from the 

 ground. The brown line marking the covered gallery was 

 very distinct against the pale bark and visible for quite a 

 distance. Bits of broken termites' nests were abundant 

 on the ground in this part of the forest. 



