INTRODUCTION. 3 
of the Equator; and beginuing to the westward on the slopes of 
Tunguragua and Llanganati, it subsides gradually into the great 
plain; it is traversed by the river Pastasa, and the Bombonasa 
rises in it. 
5. The Peruvian Andes, extending from the Maraíion on the 
north to about Lake Titicaca on the south. Plants were gathered 
only in the valley of the Huallaga, up to 5000 or 6000 feet alti- 
tude, among the easternmost undulations of the Cordillera, in 
what has been elsewhere called the Maynensian Andes, because 
included in the ancient provinee of Maynas. The river Hual- 
laga itself belongs to this division from the first cataracts up- 
wards; but from the cataracts and the Pongo (narrows) of 
Chasuta downwards, it belongs to the Amazonian plain. The 
altitudes are given in English feet (whereof 1000=305 metres). 
Those localities to which no altitudes are affixed are all in the 
Great Plain, whether on the Amazons, Rio Negro, or Orinoco, 
and none of these are probably higher than 1000 feet above the 
sea-level. 
The enumeration comprises all the Mosses which have been 
found in the continent of South America, including all those 
portions of Central America which are south of the Tropic of 
Cancer, the West-Indian Islands, the Falkland Islands, and the 
Island of Juan Fernandez, as well as all the islands contiguous 
to the mainland. 
Surveying the whole Moss-flora of these vast regions, the rich- 
ness of some genera in species, the poorness of others, in comparison 
with other corresponding regions of the earth, becomes imme- 
diately evident. About half the known species of Campylopus 
are found in South America; Leptodontium and Holomitrium 
are equally rich, but no species of the last-named genus has been 
received from the western side of the Andes. Tortuloid Mosses 
are very numerous, but all those approaching European forms 
(Barbula and Syntrichia) appear to be confined to the Andes or 
to their western side. 
Orthotrichoid Mosses of the genera Orthotrichum and Zygodon 
are very numerous; but these genera appear to be restricted 
to the Andes and their western side, as in the case of the Tor- 
tulee. Macromitrium, however, the richest genus in the number 
of its species, abounds most in the West-Indian Islands and the 
more equatorial regions of the eastern side of the Andes; and 
the great bulk of the species belong to the section Leiostoma, 
B2 
