1903 | FLORA OF SOUTHERN CALIFORNIA yy A 
COMPARATIVE RICHNESS OF THE FLORA. 
A few figures are given below showing the comparative num- 
ber of species in the southern California and some other floras. 
The last column indicates the proportion which the species of 
each flora bears to that of America north of Mexico. 
COMPARATIVE TABLE OF FLORAS. 
Region Authority Date | scAtthicg| Species | piles | Per 
Species 
N. Am. excl. Mexico | Heller, Cat. N.A. Pl. 1898 | eecxs 14,534 
N. & NW. U.S. 
Canada, etc. Britt. & Br, Ub FL FOO cro 2 AJ02 | 2.2.) 26 
io ellerman, Cat 1899 | 39,964 | 2,025 | 19.7 | 14 
Michigan Beal & Wheeler, Mich. Fl.}| 1892 | 56,451 1,740 | 32.3. |) 12 
Mont Ryd ; ont oo |145,776 | 1,676 | 89.8] 11 
Mohr, Ala. P OI | 50,2 2,525 | 200:1 IF 
Calif rew. & Wats., Bot. Cal. | 1880 {156,511 | 2,956 | 52.9 | 20 
Southern ore Parish, MS. Cat. 1900 | 40,889 1,981 | 20.6 | 13 
Great Brita Lo ndon, Cat. 7th. Bd: 1877 | 89,077 1,665 | 53-5 
The superiority in number of species of the flora of Ohio, a 
state having nearly the same area as southern California, is 
unexpected, in view of the far greater diversity of physical con- 
ditions in the latter region. To some extent this is due to an 
estimate of specific values somewhat more conservative in the 
enumeration on which the southern California figures are based 
than obtained in that for Ohio. But mostly it is owing to the 
fact that the Ohio flora has been long studied, and by numerous 
able botanists, while our own has had few students, who have 
worked under disadvantages, and for a relatively short time. 
Our flora, consequently, is known imperfectly, while that of Ohio 
has been worked up thoroughly. Additions to it must come 
mostly from occasional new introductions, or from the segrega- 
tion of known species. But with us every year’s observations 
of the few resident botanists add a considerable number of spe- 
cies, either new or not previously reported from our region.” 
Other additions are frequently made by those who restudy the 
accumulated material in the great herbaria. Much territory 
remains almost wholly unexplored, some of which is certain to 
* Since my catalogue was completed in 1900 enough additional plants have been 
Teported to make the total number considerably over two thousand. 
