DESCRIPTION OF TROCHOPTERIS. 73 
Description of Trocnopreris, a new Genus of Ferns. 
By GeorGe GARDNER, Ese. 
(With a Plate, Tab. IV.) 
AvrHOUGH Brazil has been long famous for the number of 
its Ferns, it is not perhaps generally known, that by far the 
greater part of them are confined to a limited tract of that 
great empire. The centre of this tract is the dense and 
humid forests which exist on the mountains, in the imme- 
diate neighbourhood of Rio de Janeiro; the still denser ones 
which cover the lower regions of the Organ Mountains; and 
those of the continuations of that chain which stretch towards 
the S.W. and the N.E. Shade and humidity, combined with 
heat, being the principal requisites for their growth, it is only 
where these exist that Ferns abound. The northern and inland 
provinces are for the most part composed either of immense 
Campas, as in the province of Piauhy in the north, and Goyaz 
In the west, which towards the end of the dry season, become 
little better than arid deserts ; of districts a little more ele- 
vated covered with low woods, which in the dry season 
throw off their leaves, and present the same appearance 
which the woods of cold climates do in winter—heat ef- 
fecting in the one instance what cold does in the other ;—or of 
tracts of upland, undulating, sterile, rocky, or grassy country, 
as in the Gold and Diamond districts. These parts of Brazil 
consequently afford but few ferns, although all of them 
"ré otherwise very rich in botanical productions. This, 
also, explains why later travellers in Brazil have found 
So few new ferns in comparison with those who first visited 
the country, 
During the few months, however, which I passed in the 
neighbourhood of the Villa de Natividade in the north of the 
province of Goyaz, I was fortunate enough to discover several 
Very interesting species, among which, besides the one now 
about to be described , L may mention four species of Adiantum, 
Së othochlena, a Cassabeera, a Trichomanes, a very small 
CroSlichwm, two species of Cheilanthes, and about half a 
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