10 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
differences, similar characters must be given equal consideration in 
all families. 
The Pacific northwest is a region with great physiographic and 
correspondingly great climatic differences. In consonance with the 
physical factors there are many and striking peculiarities in the dis- 
tribution of the plant species occupying this area, and the attempt is 
here made on the basis of the writer’s familiarity with the region, 
and the recorded data of others, to determine some of the complex 
‘auses which have brought about the present plant distribution. 
It is more than possible that some of the conclusions here reached 
or suggested may be based quite as much on our lack of knowledge 
as on definite information. While this may eventually prove to be 
the case, the suggestions here advanced may nevertheless serve as 
working hypotheses when a more complete botanical survey shall be 
undertaken. 
Many of the data upon which the origin of the present flora of 
Washington depends must be sought to the southward, a region here 
considered only incidentally, but which must needs be more fully 
explored before certain conclusions here suggested can be either veri- 
fied or overthrown. 
THE BOTANICAL EXPLORERS OF WASHINGTON. 
The following brief account of the botanical explorers of Wash- 
ington refers to their labors mainly in so far as they concern the 
region covered by this work. Inasmuch as both Washington and 
Idaho were included in Oregon until 1853, many of the earlier col- 
lections in these States are ascribed simply to “ Oregon,” though 
Washington and north Idaho are sometimes referred to as “ Upper 
Oregon,” notably in Geyer’s explorations. Before the name Oregon 
became attached to the northwest Pacific region the interior portions, 
especially south Idaho and eastern Oregon, were more or less vaguely 
included in “ Upper California,” a phrase not unusual on Douglas’s 
plant labels, and quite frequently used in the Botany of Beechey’s 
Voyage. Still earher than this the name “ New Georgia ” was em- 
ployed, mainly for the region bordering Puget Sound and the Gulf of 
Georgia. The most vague term of all, “ Northwest Coast,” has been 
made by different writers to include everything from the northern 
boundary of California to Prince William Sound, Alaska, and the 
approximate meaning of tliis phrase can be gleaned in each case 
where used only by indirect means. 
The botanical explorations of Washington are conveniently grouped 
into two periods. The first of these includes all the explorers previous 
to 1860, namely, Menzies, Lewis, Douglas, Scouler, Tolmie, Gairdner, 
Wyeth, Nuttall, Pickering and Brackenridge, Geyer, Spalding, Jef- 
