xxxii 
BOTANY. 
Solidago nemoralis. Lemna Valdiviana. Schollera graminea, 
Utricularia minor. Arc. polyrrhiza. Sciqjus Torreyi. 
Gentiana detonsa. Mt. Arc. Sparganium eurycarpum. Subarc. Carex aristaia. Arc. 
Rumex Britannica. Potamogeton lonchites. Agrostis elata. ? 
Ceratophyllum demersum. gramineus. Arc. Muhlenbergia sylvatica. ? 
Parietaria Pennsylvanica. Mt. perfoliatus. Arc. Eragrostis Purshii. 
The remaining plants of the valley flora arc those which in a much 
greater variety both of genera and species occupy the drier sandy or gravelly 
portions of the valleys and the foothills, and are consequently subject to a 
greater extreme of heat and drought. Many of them are low or dwarfed 
annuals, often varying much in size and habit with the circumstances of their 
growth, usually starting with the rains of autumn, flowering in early spring, 
and hastening to a cpuck maturity. With the first heats of summer they are 
burned away and speedil}^ vanish. Others are stouter and hardier, frequently 
becoming more or less woody, or are biennials or perennials springing from 
bulbs or from thick and usually deepseated "roots or root-stocks, and in the 
partial protection afl^brded by the larger shrubbery are able to maintain their 
growth till later in the season. By the middle of July, however, the far 
greater number have wholly disappeared and only the more w^oody based 
perennials are left, except in favored locahties. 
These comprise all the peculiarly ''desert" species of this portion of the 
Basin. Of the entire number (305) one-third (94) are so far as known 
strictly confined to the Basin, and on the whole southern, quite a large num- 
ber extending southward into the Mohave and Colorado deserts and half a 
dozen southeastward to New Mexico or even Western Texas. Another third 
(84,) the first section of division (^), range only westward, some to Southern 
California but nearly one-half (38) to Oregon or Washington Territory, 
though only a single one, Matricaria discoidea, is reported from farther north. 
Of the 106 which are found in the Eocky Mountain region, 63 belong also 
to the Pacific slope and as many more pass cast of the range, though only six 
are arctic or subarctic. There are also here at least 20 Mexican species and 
53 others that have been collected in Arizona. Of the 21 still more eastern 
species in division (c.) five are not found upon the Pacific side and six reach 
the arctic or subarctic portions of the continent. About half extend into 
Mexico or Arizona. As many as in the last group (51) are noted as ascend- 
ing above the foothills, but rarely to any great altitude. Only Artemisia 
tridentata, Gilia congesta, and one or two other species sometimes reach the 
summits of tlie higher ridges. 
