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 Joauqin. 



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 modifications to 

 suit temperature conditions extends from the upper Columbia drain- 

 rge to the Colorado. Here branch off the TJliginosi. A. vallaris and 

 Bolanderi represent an inflated and stipitate group reminding one 

 rf the sessile A. lentiginosus of the Inflati, the one species growing 

 en the upper and eastern Columbia drainpge, and the other in the 

 rorthern Sierras. This group abounds in the sagebrush region where 

 nlkali is not excessive. Still another specialized member reminding 

 one 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 closely 

 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 Atlantic 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- 

 nosi 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 Dyallii are plants of the sage- 

 brush plains and sandy slopes of the unper southern Columbia Basin. 

 A. Brauntoni is a remarkable modification of the plains of the reeiou 

 ■"'est 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 

 b-^tter located as an indei^endent branch of the Homalobi near the 

 Atrati or of the Atrati itself. On the other hand it has some char- 

 acters of the Argophylli. ns though a branch of the Flexuosi. 



IG. Atrati. This .group also branches off from the Homalobi 



