62 PITTONIA. 
Fertile plains of the Sacramento River, in middle and 
northern California; the best specimens collected by myself, 
near Chico, June, 1890; but there exists in the U. S. Her- 
barium a good one from the Wilkes Expedition obtained 
near Sacramento. 
X. CALIFORNICUM. Stout and freely branching, the stem 
scabro-hispidulous and the leaf-surface very rough with 
short sharp strigulose hairs, the veins bearing some that are 
longer and strigose: leafoutline broadly and angularly 
ovate, the margins unevenly double-dentate: fruiting invo- 
lucres many and densely clustered in the axils, oblong- 
ovoid, about an inch long, pubescent and somewhat gland- 
ular between the only moderately crowded prickles, these 
rather short and stout, sparsely white-hispid toward the 
base, otherwise naked; beaks a little longer than the 
prickles, stout, hispidulous and glandular, somewhat in- 
eurved from the base and also hooked. 
Common in middle California, especially about San Fran- 
cisco Bay, being the X. Canadense of my Manual and of the 
Flora Franciscana in large part. 
X. ACUTUM. Stems naked and purple-streaked below, 
hispidulous above: leaves obscurely and inequilaterally 
ovate-trigonous, nearly truncate at base, very acute or almost 
acuminate at apex, unevenly serrate-toothed on the margin, 
hispidulous-scabrous and with copious small resin dots 
among the hairs: fruiting involucres racemose or subum- 
bellate in the axils on a peduncle an inch long, with also a 
sessile one at base of the peduncle, or the uppermost all 
sessile and glomerate, each involucre about $ inch long, ob- 
long, rather sparsely echinate, both the body of the invo- 
luere and its prickles toward the base invested with sessile 
resin glands and a few short white hairs; beaks little ex- 
ceeding the prickles, straightish and little divergent, gland- 
ular and white-hispidulous. 
