220 PITTONIA. 
from T. tridentatum. Its geographie range is quite exten- 
sive, and, as I now know its distribution, it should have had 
a place in the Bay Region Manual, for several of my former 
students gathered it in Contra Costa Co., and it is found all 
the way from Monterey and Amador counties southward. 
Another good segregation from Mr. Watson's T. tridenta- 
tum is 
T. Watson, Lojacono. This belongs to the interior of 
California northward, and seems to be more restricted in its 
range than T. aciculare. 
T. SCABRELLUM, Greene, Pitt. i. 159., is to be maintained 
as originally defined. Its reduction to the rank of a mere 
variety came about through my having attempted to refer 
to it a much more common plant which was not to be con- 
founded with T. tridentatum, and which has some points of 
agreement with T. scabrellum. This I now name and de- 
fine as follows: 
TRIFOLIUM TRIMORPHUM. Annual, slender, branched from 
the base and decumbent, the branches } to 1 foot long; 
herbage light green and glabrous; leaflets of three distinct 
forms on each plant; the lowest very small and obcordate, 
barely 2 lines long, the middle cauline twice as long, linear 
and truncate, the upper oblong-linear or oblong, acute, 4 to? 
inch long, all except the lowest (these merely dentate) serru- 
late: slender-peduncled heads about 2 inch broad; involucre 
cleft to the middle into alternately long and short subulate 
segments: corollas flesh-color with a purple center ; calyx | 
evenly and strongly 10-nerved, the oblong-ovate segments 
mostly 3-dentate, shorter than the tube: pods little longer 
than the calyx-tube, 2-seeded. 
Known only from the counties of Alameda and Contra 
Costa in middle California, where it inhabits rather flat open 
grounds. Itis plentiful in the lowest parts of the Livermore l 
Valley, and occurs between Berkeley and West Berkeley; 
