21 
Sierras, and A. pterocarpus along the head of the Humboldt. Then 
come the stipitate A, sclerocarpus of the Columbia Basin sand dunes, 
A. bicristatus of the canyons of the Mojave, A. Serenoi and: canonis 
of the alkaline seeps of the east base of the Sierras, and A, pachypus 
of the similar seeps at the head of the San Joaugin. 
10. Preussii. This group is one with pods more inflated and 
mostly less fleshy, with leaves not modified and growing in: hotter 
and less alkaline places and belonging mostly along. the Colorado 
drainage, it seems to branch off early from the Podo-sclerocarpi. 
The purple flowered forms A. Preussii and ampullarius with re- 
duced number of leaflets and thin-walled and inflated pods .nor- 
mally stipitate, and A. limatus with ample. leaflets and fleshy and 
less inflated pods. A. Preussii goes from the Sierras to Colorado, 
ampullarius is local near the Kaibab, and  limatus belongs in the 
Death Valley-Mojave region. The white or cream colored flowers 
have the rather tall A. oocarpus, a near relative of A. Preussii ‚from 
the San Diego region, the remarkable A. asclepiadoides, probably 
nearest to A. ampullarius, of the Navajo Basin and upper Sevier, 
with a single’ great leaflet, and the fleshly-walled A. Pattersoni and 
sabulosus, also of the Navajo Basin, A. Pattersoni also going over 
into the Great Basin and on the Rio Grande drainage. 
11, The other branch of the Collini is the. Reventi-arrecti where 
this line runs toward the production of the septum into 2-celled pods. 
A. reventus and adanus represent the fleshy-walled side and: belong 
in the Columbia drainage. A. arrectus in its many modificationg to 
suit temperature conditions extends from the upper Columbia drain- 
age to the Colorado. Here branch off the Uliginosi, A. vallaris and 
Bolanderi represent an inflated and stipitate group reminding one 
cf the sessile A. lentiginosus of the Inflati, the one species. growing 
on the upper and eastern Columbia drainage, and the other in the 
northern Sierras. This group abounds in the sagebrush region where 
alkali is not excessive. Still another specialized member reminding 
ene of the Sarcocarpi is A. accidens with plum-shaped and very 
fleshy stipitate pods inhabiting the pine forests of the Cascades, like . 
its congener A. Bolanderi of the Sierras farther south, 
12. Uliginosi. 'This early branch of the Reventi-arrecti is close!y : 
related to it through A. terminalis and Oreganus, Species of the up- 
per Columbia drainage and adjacent head of the Missouri, growing 
in sagebrush regions. A. Canadensis comes next with. its stubby 
flowers and is cosmopolitan, from the Atlantie to the Pacific, growing 
in copses and prairies. A. neglectus an inflated modification remind- 
ing one much of the Preussii belongs in the Minnesota region in 
open woods. 
13. Hypoglottides. this appears to be an offshoot of the Uligi- 
vosi as shown by the flowers, habitat, and pubescence of A. nitidus. 
The first species A. nitidus belongs on the Plains and extends west- 
ward to Washington. A. agrestis belongs in the sweet and cold 
meadows of alpine and subalpine regions for the most part, though - 
it goes down into Middle Temperate in specially favorable places. 
Both species endure small amounts of alkali. This group is Asiatic 
and European and reaches a much better development there. 
14. Chaetodontes.. This group seems a natural modification of 
the Hypoglottides. A. Austinae is a caespitose modification of rocky 
ridges in the Sierras. A. Spaldingii and Lyallii are plants of the sage- 
brush plains and sandy slopes of the upper southern Columbia Basin. 
A. Brauntoni is a remarkable modification of the plains of the region 
west of Riverside California. This makes the end of the Collini 
branch of the Homalobi. — 
` 15. The Lotiflori is a group that is hard to place but seems 
better located as an independent branch of the Homalobi near the 
Atrati or of the Atrati itself. On the other hand it has some char- . 
acters of the Argophylli, as though a branch of the Flexnosi. 
16. Atrati. This group also branches. off from the Homalobi 
