382 NOTES OF A BOTANIST 
To Sir William Hooker 
San Carlos, Sept. 17, 1853. 
In the angle between the Rio Negro and Casiquiari I have 
got some Mosses and Hepaticae that have interested me much. 
As my predilection for these tribes is known to many, you may 
perhaps have been asked whether I was doing anything in them, 
and if I intended to distribute the species. I have hitherto 
avoided alluding to Mosses in my communications to you because 
the number was so few that I had no idea of their ever summing 
up to a quantity worth the trouble of distribution. 
On the Alto Rio Negro I have been more successful, and I 
now think, that some day or other I may make up sets of those 
Mosses and Hepaticse which I have gathered in sufficient quan- 
tity. Of Mosses the number of species is still small, considering 
the space of ground passed over, and how sharply I have looked 
for them during four years of travel. I suppose that in all this 
time I have not gathered more Mosses than I could have 
gathered in a month in the space of fifty miles diameter in any 
part of Europe. Yet all are interesting and a good many will be 
new. The general character of the cryptogamic vegetation on 
the Amazon and Rio Negro seems to be quite that of Demerara 
and Surinam, and to bear little resemblance to that of the rest 
of Brazil. The Mosses are mostly pleurocarpous, and comprise 
a great number of minute Hypnums and a good many Hookerias. 
A pretty species of the latter genus, frequent on logs in the 
moist forest near San Carlos, seems to be the Hookeria pallescens 
which you described in Musei Exotici from specimens gathered 
by Humboldt at Esmeralda. I shall endeavour to look up all 
Humboldt's species from this region. Among acrocarpous 
Mosses the commonest and perhaps the most beautiful is 
Octoblepharum albidum, which grows everywhere on trees, both in 
wet and dry situations. O. cylindricum is much less frequent, 
and I have mostly seen it on palm trunks. I expect I have one or 
two new species of this genus ! There are a good many minute 
Fissidens whose habitat is chiefly on termites' nests on the 
ground or in trees. The genera Macromitrium, Syrrhopodon, and 
Calymperes have all representatives, but they are far from being 
so abundant as I expected to find them. On the other hand, I 
have met with species of some genera considered peculiar to 
cooler climates, as, for instance, an Anacalypta at Santarem and 
a Phascum at Sao Gabriel. On the Rio Negro a very common 
and a very handsome moss is Leucobryum (^Dicranuni) Mar- 
tianum ; it grows on wet logs, and has the additional merit of 
fruiting copiously. I have been somewhat disappointed that 
