198 LEAFLETS. 
I. ATRATUS. Stems erect, simple, 1 to 2 feet high, bearing a 
simple and short raceme of large dark-purple flowers at summit; 
herbage glabrous, glaucescent; leaves oblong to linear, sessile : 
sepals tipped with a somewhat abrupt long acumination: pet- 
als nearly 3 inch long, the oblong limb much wider than the 
narrow claw, of very dark purple, almost blackish: pods not 
known. 
Along the Canadian River, Indian Territory, M. A. Carleton, 
June, 1891; type in U. S. Herb. 
There is a type inhabiting the deserts of the Great Basin and 
of southeastern California which has been masquerading for 
half a century as a Lepidium with yellow flowers ; a circumstance 
which Doctor Torrey himself in publishing the species consid- 
ered very extraordinary for a Lepidium and he therefore named 
it Z. flavum, regarding this as the most salient feature of a 
species, which nevertheless, has other and more significant pecu- 
liarities. Not only the flowers but also the whole herbage is yellow 
—at least decidedly yellow-green. Its stout depressed branches 
are more or less definitely dichotomous, bearing in the forks and 
at the ends, not the racemes of any Zefidium, but short subum- 
bellate clusters of flowers and pods commonly broader than 
high. The lower pedicels of this cluster are leafy-bracted. The 
pods themselves are surmounted by a stout persistent style of 
half their own length, while in most lepidia there is no trace of 
any style at all. 
Here are then, five points of divergence from each and every 
section of Lepidium that can be brought into comparison with it ; 
and the aggregate of all these marks of this annual of western 
deserts, gives to the type an aspect more like that of certain 
desert genera of capparids, such as Oxysty/is and Wisisenia, 
than like any genus of cruciferae that can be mentioned. 
Three subspecies of SPRENGERIA are well isolated geographi- 
cally, and may take names as follows : 
S. FLAVA. The original of Z. flavum, Torr., restricted to the 
