2o6 NOTES OF A BOTANIST 
sinks over the knees in black, white, and red mud. A wood of 
young larches may give you an idea of its appearance. I have 
never seen anything which so much astonished me. I could 
almost fancy myself in some primeval forest of Calamites, and if 
some gigantic Saurian had suddenly appeared, crushing its way 
among the succulent stems, my surprise could hardly have been 
increased. I could find no fruit, so that whether it be terminal, 
as in E. giganteum, or radical, as in E. fliiviatile^ is still doubtful, 
and for this reason I took no specimens at the time, though I 
shall make a point of gathering it in any state. 
Mount Tunguragua is nearly as fine a locality for ferns as the 
forest of Canelos, but great difficulties attend its ascent. First, 
there is the actual height, for Bahos is but 5500 feet high, and 
from thence to the snow-line (15,000 feet) is a great way to climb. 
Then there is the want of water, for between Bahos and Puela, 
that is, for about five leagues along the northern base of the 
mountain, all the ravines are dry. The streams that formerly 
traversed them all became submerged when the great earthquake 
of 1797 took place, and now run in subterranean courses, coming 
out on the actual margin of the Pastasa, sometimes in consider- 
able volume. But the greatest obstruction to the ascent is the 
dense, untracked, quasi- Amazonian forest, to penetrate which the 
knife is needed at every step, and which extends to a height that 
I have not yet exactly ascertained. I could not have believed, 
unless I had seen it, that at 11,000 feet elevation on Tunguragua 
there are laurels 70 feet high and 12 feet round. 
I trust my collections will not disappoint your expectations ; 
they do not, however, quite come up to mine, for I have suffered 
much here from the cold, and especially from the sudden alter- 
nations of burning heat to frosty cold, and I have consequently 
been unable to do so much field-work as I could wish. Since 
entering the Ecuador I have gathered forty-five species of Poly- 
podium (including Goniophlebium, etc.), all, with two or three 
exceptions, different from what I gathered in Peru. They include 
some very pretty things, especially in Polypodium proper. I have 
also some pretty Asplenia ; but the species of this genus and 
Diplazium give me more difficulty than any other — to know what 
are species and what varieties. 
[The next letter to Mr. Bentham contains, 
among other valuable botanical matter, an exceed- 
ingly interesting estimate of the probable number 
of species of plants now living in the great Amazon 
valley, founded on his own observations. It is 
