1918] 
PAYSON—NOTES ON CERTAIN CRUCIFERAE 147 
Distribution: eastern Oregon. 
10. P.alpestris Suksdorf, West Am. Scientist 15 : 58. 1906. 
Distribution: south central Washington. 
Diruyrea Harv. 
This North American genus differs from the Mediterranean 
genus Biscutella in three conspicuous ways. Dithyrea has 
branched hairs, a stigma, the lobes of which extend over the 
middle of the carpels, and a replum of two distinct limbs 
which subtend a narrow, though evident, septum. Biscutella, 
on the other hand, exhibits unbranched hairs, a stigma, the 
lobes of which extend over the placentae, and a replum with 
fused limbs and obsolete septum. Although the two genera 
seem amply distinct, it appears impossible to accept Prantl’s 
view that they belong in different sections of the family. 
Key то SPECIES AND VARIETIES 
A. еле Mr pubescence of pods branched or stellate. 
s thick, lanceolate to linear, densely pubescent. 
тане narrowly lanceolate to linear; stems branch- 
ОТАП. бла а ТТТ ТТТ OUT la. var. Griffithsii 
B. Leaves broadly lanceolate; stems inclined to be 
strict. 
I. Leaves cuneate at the base................. 1. D. Wislizenit 
II. Leaves truncate at the RE e; stems ict....1b. var. Palmeri 
b. Leaves thin, ovate or oblong, sparingly bac .2. D. membranacea 
B. -— tubular; pubescence of pods of flattened unbranched 
a. “style about 0.5 mm. long; mature pods 6-8 mm. broad. 
a 
Corolla dull white; ща plantas 5 ты 3. D. californica 
. Corolla purplish; beac THONGS одат пое За. var. maritima 
b. E. Каи ог quite 1 mm. long; mature pods 3—4 
сайгу; аума ОГОЛОК ТОСКОЛ 4. D. clinata 
1. D. Wislizenii Engelm. Wisliz. Tour N. Mexico, 95. 1848. 
Distribution: western Texas, southern New Mexico, and 
adjacent Mexico. 
D. Wislizenii in the aggregate exhibits within its large 
range three fairly distinct but more or less arbitrarily limited 
phases. Fortunately enough, the type was collected from 
near the geographical center of distribution and represents 
a form intermediate between the two varieties. The species 
in its typical form passes gradually on the east into the 
variety Palmeri and on the north and west into the 
