25 
species related to it and to A. hirtum, all having the same ecological 
character. All our Loxogramme species dry up and shrivel during pro- 
longed drought but do not lose their fronds. 
The epiphytes of the high forest include no really tropophytic element, 
since the plants just mentioned, always ready for drought and able to 
recover instantly from it, are ratlier to be considered as xerophytes. Tt 
has already been noted that Drynaria is a potential tropophyte^ which, 
in the high forest, usually retains its foliage. The strong representation 
of Aspleninm, Loxogramme, Ilumata and DavaUia, and Phymatodes and 
its derivatives, Niphohohis, Drynaria, Dryostachyum, Lecanopteris and 
■ ■ 
riwtinopteris, and the absence of Eu-Poly podium, are floristically notable 
among the high forest epiphytes. 
THE RAIN FOREST. 
The rain forest is our most constantly humid region. The deep 
canons in the upper part of the higli forest belt preserve a moist atmos- 
phere when the neighboring uplands have become dry, and in these 
canons the flora merges, formally and floristically, into that of the rainy 
forest. In the rain forest the air is everywhere moist, and so few species 
And anything like a dry habitat that all the terrestrial plants are best 
grouped together. The dry, Taenifis- and Polystichurn'markG^ ridges 
of the upper high forest flatten out and the ridges that rise in turn from 
/ + 
the rain forest, although at times arid because of their exposure, are 
floristically most distinct. The characteristic ferns along these upper 
ridges are Cheiropleuria and Dipteris. There are^ of course, places 
where ridges continue across the rain forest, but, where I have visited 
them, the vegetation plainly showed that they were more constantly 
humid than the ridges above or below. 
As compared with the high forest the rain forest above San T?amon 
is a very limited area. It is very inaccessible, absolutely trailless and 
uninhabited and I was certainly the first white man to visit it, and then 
I was able to enter it but three times, for a day each ; wlien this is con- 
r 
sidered and the number of species which I collected is understood, its 
real wealth of ferns will begin to be appreciated. I have little doubt 
that its actual wealth in species is greater than that of the high forest. 
Of course aside from trees^ ferns are here the dominant and characteristic 
vegetation. The luxuriance of this fern vegetation in the number of 
individuals and in the size thereof, is beyond the comprehension of 
anyone who has not seen it. A large majority of the terrestrial species 
reach to a height of above 1 meter; several are commonly above 2 meters; 
Aspidium lenzeanum var. and Dlplazium fructuosum are some 4 meters 
in height, stipe included; and an enormous Dennstacdtia has a tuft of 
spreading fronds reaching more than 7 meters. 
Small streams evervwhere thread this wilderness and furnish the most 
