Chap. I] CHARACTERS OF THE TROPICAL CLIMATE 



129 



Main!)-, but not cxcliisivcl)-, tropical are the Cyatheaccac, to which ahnost 

 all tree-ferns belong (species of C}-athea, Dicksonia, Alsophila), and the 

 Ilyincnophyllaccac, small, frequently moss-like herbs with transparent 

 foliage, which cover stems of trees and rocks in moist, shady forests, just 

 as mosses do with us. 



The great mass of tropical ferns belongs to the ovdev Polypodiaccac, which 

 is also so strongly represented in Europe, and to a considerable extent by 

 the same genera, namely Polj-podium, Aspidium, Asplcnium, Pteris, and 

 50 on. Onh- a few rare Pol\-podiaceae are tree-like. 



Fig. 116. Forest lanilscape in the Seychelles. In the foregronnd, Gleichenia linearis; in the 

 ackground, palms (probably Uoscheria melanochaeies, H. \Vcndl.\ Pandanus, and other plants, 

 "rem a photograph by A. Brauer. 



The Lycopodiaccac are much less prominent than the ferns, but neverthe- 

 ess of greater significance than in temperate floras. Species of Selaginella 

 ftcn form the chief covering of the forest soil ; Lycopodium cernuum is 

 :xtremely common in well-lighted spots ; other species of Lycopodium as 

 veil as of Psilotum are occasionally common epiph\-tes. 



The Eqiiisctaccac are not more strongly represented than in the 

 emperate zones. 



