81 
` can region into Arizona. Professor Harshberger introduces his 
list with the following remarks (see page 244): “The mere botan- 
ical enumeration of the following species of trees gives no proper 
idea of the arboreal flora of the region." Certainly, as the list 
is made up, it does not. Abies grandis, common in the north- 
west, Sabina monosperma, in the south, Populus acuminata, P. 
Wilslezeni, Alnus tenuifolia, Acer glabrum, the two species of 
Tsuga, several of Salix and Betula, etc., are omitted. Further 
down, he remarks: ‘‘From the whole region oaks are conspicu- 
ously absent as trees.” Quercus macrocarpa (found, however, 
only in the Black Hills) and Q. leptophylla are always trees; Q. 
ulahensis, Q. Gambellii, Q. neomexicana and Q. subtomentosa are 
sometimes trees 20 to 30 feet high. 
A good phytogeographer should carefully consider the geo- 4— 
graphical distribution of the different species; (I) not cite them 
from a region where they do not grow; (2) carefully consider to 
which regions or zone they really belong and to what extent they 
have invaded other districts; (3) whether they are the charac- 
teristic or primary species of a certain zone or are only incidentally 
found there. Many data can be had from printed reports, but 
as noted above many of the reports are very unreliable and most 
of them need verification. A good deal of personal field work is 
imperative, but if such is impossible or unfeasible, the same result 
can practically be gained by studying the collections in our" 
greater herbaria. If Professor Harshberger had studied a little 
‘more the herbaria at the University of Pennsylvania and the 
Philadelphia Academy of Sciences, which are easily accessible to 
him, I think that many misrepresentations of the geography of 
individual plants could have been avoided. I shall mention only 
a few from the Rocky Mountain Region. On pages 246-7 is 
given a list of 26 woody plants from California [Italics are mine], 
which enter the northwest of the Rockies and extend “only as 
far as the Bitterroot Mountains in Idaho." In this list are in- 
cluded Pinus albicaulis, which is not really a Californian tree 
and is found in Montana east as well as west of the divide and 
also on the Yellowstone Plateau; Artemisia discolor var. incompta 
and A. ludoviciana, which are by no means woody and the latter 
