THE SPECIES OF RHAMNUS IN SOUTHWESTERN 
UNITED STATES AND THE PACIFIC COAST 
AND PUCCINIA CORONATA 
L. H. PAMMEE 
Brewer and Watson 1 in the Botany of California list four 
species and one variety of the genus Rhamnus in California as 
follows : Rhamnus alnifolia, R. crocea, R. calif ornica and var. 
tomentella and R. Purshiana. Jepson 2 in his Flora of Western 
Middle California lists three species and two varieties, the only 
addition to that of the flora of California being the variety ilici- 
folia. Trelease 3 in his revision of North American Rhamnus re- 
cords the following species and three varieties of Rhamnus of 
Western United States : Rhamnus crocea Nutt and var. pilosa, 
R. alnifolia, R. Purshiana, R. Calif ornica var. tomentella and var. 
rubra. Coulter 4 lists two of the Pacific Coast species in Western 
Texas, the R. Purshiana and R. calif ornica. It is not probable 
that either of these species occurs in the mountains of Western 
Texas as reported. The recorded western species are referable to 
other species occurring in New Mexico and adjacent regions west 
and north. Wooten 5 however recognizes none of the Pacific coast 
species. The four species enumerated by him are R. fasciculata, 
R. Smithii, R. . ursina and R. betulaefolia. These species were 
segregated by Greene from the Pacific coast species previously 
recorded for the region. 
It is interesting to note that there are only two native species 
of Rhamnus in Iowa, namely R. lanceolata and R. alnifolia, be- 
sides the occasionally naturalized R. cathartica. The Pacfic coast 
species of buckthorn are extremely variable and it is doubtful 
whether the number of species recognized by some North Amer- 
ican botanists is entirely justified. 
Rhamnus California Esch. is one of the most common and 
variable species of the genus in California. This is a tall shrub, 
with somewhat tomentose twigs, lower surface of leaves glossy 
or pubescent, upper surface dull green. The California buck- 
thorn produces fruit abundantly. It occurs on margins of streams 
or forms a low undergrowth in coniferous woods. The altiitudi- 
1 1: 100-101. 
2 251-252. 
3 Trans. Acad. Sci. St. Louis 5; 365-367; 1892. 
4 Botany of Western Texas : Contr. U. S. Nat. Herb. 2; 60; 1891-1894. 
5 Flora of New Mexico: Contr. U. S. Natl. Herb. 19 ; 414-415 ; 1915. 
