-March 7, 1913 27 
T. columbinum has a much wider distribution than is gen- 
erally supposed. McDermott states that it “is rare, not found 
some seasons,” and collected only in middle western California. 
Our investigations show that it occurs all the way across the 
state from Sonoma to Amador counties. It can not in any 
sense be considered a form of olzvaceum,as it has a different 
floral structure. The drawing of the vexillum of 7. ol:vaceum 
on page 212 of North American Trifoliums is inaccurate. The 
apex is very broad, not pointed, as in the figure. Indeed, it is 
of almost equal width throughout (compare figures 4 and 5, plate 
1). It is also only slightly inflated at the base. 7: columbinum 
is broad at the base and gradually tapers toward the apex, where 
it is decidedly acute. It is the only species of the group in which 
this character is very pronounced. It is also very much inflated 
at the base, particularly in mature specimens. On page 214 of 
North American Trifoliums, the plate of 7: olzvaceum repre- 
sents a portion of a plant, one of the heads supposed to be o/zva- 
ceum and the other columbinum. We are led to believe that 
both species occur on the sume plant. 
The species varies considerably from the type collected at 
Vacaville, Solano county, to depauperate specimens like those 
from Ione, Amador county, Hansen 1583. The above repre- 
sent the extremes and differ somewhat in general appearance, 
but they both have the characteristic vexillum. Between these 
are a number of collections which show the gradual variation 
from the type. This is no doubt due to environmental condi- 
tions, probably aridity, poorer soil, and higher elevation. The 
following sheets are mentioned as showing the gradual variation 
of the species and its distribution: 
Near Vacaville, Solano county, Heller and Brown 5391 
(typical); Agua Caliente, Sonoma county, April 22, 1902, He/- 
ler; Clear Creek, Butte county, Brown 757, Marysville Buttes, 
Sutter county, /Yeller 7578; Chico, Butte county, Copeland 
3025, Jone, Amador county, Hansen 158 3. 
