26 Muhlenbergia, Volume 4 
- RECENT PUBLICATIONS 
COMPOSITAE OF SOUTHERN CALIFORNIA. Harvey Monroe Hall. 
Univ. of Cal. Publ. Bot. 3: 1-302. pd. 7-5. Dec. 28, 1907. 
Two tendencies manifest themselves in botanical taxonomy. 
One author, taking a broad and philosophical view, disregards 
minor differences, and groups his plants in comprehensive gen- 
era and aggregate species. In the eyes of another, minute and 
inconstant differences assume importance, and he chops his pre- 
decessor’s genera into very unequal fragments, and evolves from 
his species decades of segregates, each of which it is necessary to 
tie very tightly to a particular sheet in a particular herbarium. 
Either method has its advantages. The one mind grasps 
the broader affinities; the other detects the minuter differences. 
And certainly it is desirable that all the characters of plants, 
however ininute they may be, should be studied, and, if neces- 
sary, the plants given names. But to undertake to denote dif- 
ferences so varied in degree, by the two categories of genus and 
species, is not to express nature, but to impose an arbitrary and 
artificial nomenclature. 
In Dr. Hall’s monograph minor differences are not ignored, 
nor are they regarded as of equal importance, but are assigned 
in due subordination of rank. An excellent example is his 
treatment of the difficult genus Baeria, the despair of those 
aware of its characterless complexity, here satisfactorily untan- 
gled. A like illuminating arrangement is made of the trouble- 
some group of related forms embraced in Chaenactis glabrius- 
cula. 
Beyond question Dr. Hall has given us by far the most val- 
uable contribution yet made to the study of the southern Cali- 
fornia flora. It shows throughout the author’s careful and: con- 
scientious work, and an intimate acquaintance with the living 
plants which gives it an authoritative value. It is a long step 
toward the much desired Manual of the region.—S. B. PARISH. 
