206 NOTES OF A BOTANIST CHAP. 



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. giganfei/m, or radical, as in E. fliiviatik, 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 Banos 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 Banos 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 



