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RE POUT UPON THE BOTANY OF THE ROUTE. 
BY JOHN S . NEWBEKRY, M . D ., 
BOTANIST OF THE EXPEDITION. 
CHAPTER I. 
GEOGRAPHICAL BOTANY. 
INFLUENCES AFFECTING THE BOTANICAL CHARACTER OF THE REGION BETWEEN SAN FRANCISCO AND THE COLUMBIA.—LAWS CONTROLLING THE 
DISTRIBUTION OF SPECIES AT PRESENT NOT UNDERSTOOD.—NOVELTY OF BOTANICAL CHARACTER OF THIS REGION.—VARIETY OF AN¬ 
NUAL plants.—Small number of trees.—Preponderance of coniferas.—Climate.—Geological structure.—Local botany.— 
Coast mountains.—Climate.—Causes affecting it.—Vegetation.—Forests.—Shrubs.—Ferns and mosses.—Sacramento 
valley.—Climate, character of seasons.—Vegetation.—Its annual character.—Timber belts.—Local botany.—Wild 
oat.—Oak groves.—Shrubs.—Tule.—Character of soil.—Timber belts and thickets along tiie river banks.—Botany of 
SIERRA NEVADA.—ITS UNITY OF CHARACTER.—FORESTS.—LOCAL BOTANY.—ZONES OF VEGETATION.—ANNUAL PLANTS.—BOTANY 
OF THE DISTRICT EAST OF SIERRA NEVADA AND THE CASCADES.—UNIFORMITY OF VEGETATION. SAGE PLAINS.—YELLOW PINE 
forests.—Local botany.—Bunch grass.—Annual plants.—Botany of klamath lake.—Botany of the des chutes basin.— 
Botany of the cascade mountains.—Belts of vegetation.—Forests of willamette valley. 
The influences which have given character to the flora of the region lying between San 
Francisco and the Columbia, both as regards its botanical relations and the distribution of the 
plants which compose it, as in other countries, have been connected with its geological struc¬ 
ture, its topographical features, and its climate. 
To these causes, which are very appreciable in their action, and which have produced by far 
the most striking phenomena presented by the vegetation of the west, another should he added, 
that which has controlled the radiation of species from their original centers of creation. 
The operation of this latter cause, though perhaps not less real, is far more obscure, 
requiring for its analysis an array of facts much greater than has yet been collected. This has, 
therefore, been entirely neglected, except in the few instances where plants are common to both 
sides of the continent, and an effort has been made to connect their eastern and western habi¬ 
tats. When the botany of the west shall come to he known far better than at present, we may 
expect that the physiological laws which have controlled the distribution of plants may he 
studied with equal profit with the more material influences of which I have spoken. 
At present any hypotheses in reference to them, however plausible they may appear, must 
necessarily involve so much uncertainty, that they should he regarded as speculations rather 
than generalizations of fact. And in the future, by whomsoever theories on this subject may 
he suggested, and whatever weight or personal influence may he thrown into the scale, that 
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