22 
and near A, junceus and verges toward the Alpini and represents . 
it in the south and warmer and drier regions, It has a tendency 
to fleshy or coriaceous pods, and with ventral suture the more 
arched. A. Salmonis is a fleshy and caespitose plant of cold ridges 
in the Blue Mountains Oregon, A. obscurus has much narrower and 
less fleshy pods and frequents the sagebrush benches of northern 
Nevada. A. atratus has about straight pods and is very variable. 
It belongs in the sagebrush-juniper regions. In the Boise region its 
pods are papery and its filiform stems straggle for several feet over 
the ground, in central Nevada its stems are spreading and short and 
pods chartaceous to almost coriaceous, in the Death Valley region 
its pods are almost fleshy and rather cartilaginous. A. Ibapensis is 
like the central Nevada atratus but with different leaves and grows 
in the Deep Creek mountains on sagebrush slopes. A. Panamin- 
tensis has quite fleshy pods, but they on drying are only chartaceous. 
It grows in the rocky canons of the Panamints of California. 
17. Strigulosi. This group seems to be an early branch of the 
Atrati and like it has the ventral suture the more arched, and the 
rods are almost always stipitate and papery and inclined to inflated, 
and reflexed. A. recurvus and straturensis are in close relation with 
their narrow and linear, not inflated pods and acuminate base, and 
papery partial partition. They frequent the Grand Canon region, 
among the pines and brush. The rest of the group has oblong to glo- 
bose pods either inflated or appearing so. A, strigulosus has pods 
acuminate at base and often at tip and with loose pubescence, and 
in its various forms extends from the Grand Canon to southern 
Mexico. A. Brandegei, platytropis and Cobrensis are peculiar species 
the first and last seemingly inflated but little if at all so, and little 
if at all stipitate; the first reminds one of atratus, of the Atrati and 
may belong there near the Idaho form of atratus, and it grows from 
Canon City Colorado through the Navajo basin in the Lower Tem- 
perate life zone. A. Cobrensis is more coriaceous and frequents the 
mountains of New Mexico and Arizona in the same zone. A. platy- 
tropis a very aberrant species of the dry mountains of eastern 
Nevada, Montana and the Sierras doubtless closest related to A. 
Brandegei. This rarely gets as low as the Lower Temperate life 
zone, and has globose and greatly inflated pods, Plants with pros- 
trate stems or nearly so and elongated, and with stipitate pods, and 
plants almost wholly smooth grow in the meadows much as the 
Alpini but in central and southern Mexico. These are A. Guatama- 
lensis, Painteri, Tolucanus and Rosei, A. .similar species but creep- 
ing and rooting at the nodes is A. reptans. 
18. Flexuosi. This goes off earlier than the Collini from the 
Homalobi in the tendency of the pods to be coriaceous and round in 
cross section, and in the small flowers of the parent group. The 
parent species is A. flexuosus of the northern Plains. A. parviflorus 
is a depauperate modification of the Plains, from which branch off 
the Ocreati. Then the species become inflated and the flowers lar- 
ger and we have a natural series to the end, as the species extend 
southward. A, gracilentus connects this series with the parent and 
belongs in the dry pinon forests of Colorado and New Mexico. A. 
Sileranus is a straggling offshoot of the Kaibab region, . A. coriaceus 
and Antoninus belong in the hotter regions of Mexico, and A. pin- 
onis in the Sevier Basin Utah. ; 
19. Argophylli. This is a natural offshoot of the Flexuosi in the 
line of pod thickening. A. desperatus of the hot ledges of the Navajo 
Basin is a near relative. A. cibarius of the sagebrush plains from 
Montana to southern Utah and westward is next, then come A. io- 
danthus anl Webberi of the Sierra region. These are forms with little 
pubescence except in A. desperatus. Forms with mostly large pods 
quite fleshy and not inflated noticeably and with silvery pubescence 
not woolly are A. argophyllus of the Montana to Arizona slopes and 
plains. Shortianus of the Colorado and New Mexican plains and foot- 
