25 



is without jointing of pod to calyx and with manifest stipe. The 

 first group is herbaceous and with nearly prostrate and slender 

 stems. A. Howellii has narrow pods, is inclined to be softly pubescent 

 and with dirty-white flowers about 1 cm. long. It frequents the 

 prairies of the lower Columbia Basin. A. Mulfordse has the broad 

 and a little inflated pods smooth, and has the small flowers of A. 

 campestris, and belongs in the Upper Snake river region on sandy 

 slopes. A. Inyoensis is the only annual with long and prostrate 

 stems and brilliant purple flowers and broad and obcompressed 

 pods as in Mulfordse and belongs in the Death Valley region. The 

 next group of the Hamosi is marked by the shrubby base, woolly 

 pubescence and narrow pods. A. Nevinii has smooth pods and A. 

 Traskise has woolly pods. Both belong on the islands of southern 

 California. . A. Arthuri is a remarkable plant with almost filiform 

 and acuminate and elongated pods and the general habit of A. How- 

 ellii and belongs in the Lake Waha region of Idaho. 



29. The Leptocarpi seem to branch off from the Hamosi early 

 near the first group. The first division contains the species with blunt 

 keel, and wings not lobed, and embraces two groups, fJhe first 

 containing A. Francisquitensis, Lindheimeri and Icptocarpus with 

 smooth pods and racemose. The first species belongs in the lower 

 California region, and the other two on the Texan prairies, the latter 

 species going to central Mexico. The second group has flowers in 

 heads, and with two rather distinct segregations. A. tener and 

 Rattani belong on the California plains and have pods never shaggy. 

 A. Wrightii has shaggy pods and belongs on the Texan prairies. The 

 second division of the Leptocarpi embraces the oxytropidoid forms 

 with sharp or produced keel and a tendency to lobed wings, and 

 wings wide above. A. Taittallianus has pods arched most near the base 

 and rarely inverted on a twisted pedicel, the keel variously sharp, 

 and with obovate v^'ings. This is almost everywhere in the Tropi- 

 cal life zone and covers most of the Lower Temperate throughout the 

 Great Basin. A. acutirostris and nothoxys have acuminate keel and 

 pods inverted on a twisted pedicel. The one belongs in the Mo- 

 jave-Death Valley region, the other on the plains or low mountain 

 slopes of southern Arizona, and extending into Mexico. The flowers 

 of the Leptocarpi are seldom minute. 



30. Micranthi, This is manifestly closely related to the Lepto- 

 carpi but with pods inclined to be obcompressed and rather sul- 

 cate at both sutures. A. lentiformis is peculiar in the much laterally 

 flattened pod like A. tegetarioides, but it is manifestly an ally to 

 A. Lemmoni of the same region namely the divide between the 

 Great Basin and the Columbia drainage along the Sierras in the 

 sagebrush. This group is almost wholly Mexican, with an outlier in 

 Texas and three species reaching Arizona and California besides 

 those mentioned. Plants with pediceled flowers in racemes are A. 

 Madrensis of the pine forests of Chihuahua, the little known A. er- 

 voides of Tepic, and Luisianus also of the forests of Oaxaca and Pu- 

 ebla. Plants with flowers in loose heads and rather few are the 

 mostly woolly A. Greggii of Coahuila and southward. A. Pringlei of 

 the Chihuahua plains, A. parvus of the_ regions of San Luis Potosi. 

 and A. Schaffneri from the same region. Plants with flowers in 

 dense heads and with axillary peduncles are those with narrow 

 leaflets A. Lemmoni, from California, Esperanzae from central Mexi- 

 co, and Chapalanus from Jalisco. Plants with similar flowers but 

 broad leaflets sessile in spikes and pods about sessile have two 

 groups, with pods about linear which embrace A. Hartwegi from cen- 

 tral Mexico, A. militaris from Chihuahua and adjacent Arizona, A. 

 Saltonis from the State of Mexico, A. vaccarum from Arizona and 

 Chihuahua and southward on dry hills, and the conspicuously con- 



