274 FUNGI. 
temperate and frigid zones for their special abode, and some of 
them at times find their way to the higher regions of the Alps. 
No one can describe the luxuriance of the torrid zone in Poly- 
port and Trametes, genera of Hymenomycetes, which flourish 
beneath the shade of the virgin forests, where perpetual moisture 
and heat promote their vegetation and give rise to an infinite 
variety of forms. But though the genus Polyporus, which rivals 
Agaricus in the number of its species, inhabits, in preference, 
warm climates at large, it nevertheless exhibits species peculiar 
to each ccuntry. This arises from the circumstance that the 
Polypori, for the most part, live upon trees, and are dependent 
on this or that particular tree for a suitable habitat; and the 
tropical flora being prolific in trees of all kinds, a multitude of 
the most varied forms of these fungi is a necessary consequence. 
Hexagona, Favolus, and Laschia are common in inter-tropical 
countries, but they are either entirely absent or extremely rare 
in temperate climes. 
When the majority of the species of a genus are of a, fleshy 
consistence, it may generally be concluded that that genus 
belongs to a Northern region, even if it should have some repre- 
ventatives in lands which enjoy more sunshine. Thus the Hydna 
are the principal ornaments of Northern forests, where they attain 
so luxuriant a growth and beauty that every other country must 
yield the palm to Sweden in respect to them. In an allied genus, 
that of JIrpex, the texture assumes a coriaceous consistence, and 
we find its species to be more especially inhabitants of warm 
climates. 
Most of the genera of Auricularini are cosmopolitan, and the 
same is true of some species of Stereum, of Corticium, etc., which 
are met with in countries of the most different geographical 
position. In tropical countries, these genera of fungi assume the 
most curious and Inxuriant forms. The single and not consider- 
able genus Cyphella appears to be pretty uniformly distributed 
ever the globe. The Clavarigi are equally. universal in their 
diffusion, although more plentifyl in the north; however, the 
genus Prerula possesses several exotic forms, itena in Europe 
it has but two representative species. That beantiful genus of 
