364 MISC. PUBLICATION 4 2 3, U. S. DEPT. OF AGRICULTURE 



tentatively to that species. T.Jilipes Greene, based on a collection at 

 Clifton, Greenlee County (Davidson in 1899), may be a form of this 

 rather variable species. 



30. ATHYSANUS 



Plant annual, small, pubescent with partly forked hairs; stems 

 filiform-branched from at or near the base; racemes elongate, 1 -sided; 

 flowers on reflexed or recurved pedicels, the petals minute or wanting; 

 pods indehiscent, 1 -seeded, wingless. 



1. Athysanus pusillus (Hook.) Greene, Calif. Acad. Sci. Bui. 1: 72. 



1885. 



Thysanocarpus pusillus Hook., Icon. PI. 1: pi. 42. 1836. 



Graham, Gila, Maricopa, and Pinal Counties (probably more 

 widely distributed), 5,000 feet or lower, March to April. Idaho to 

 British Columbia, Arizona, and California. 



The type of var. glabrior S. Wats., a nearly glabrous form, came 

 from Fort Mohave (Lemmon in 1884). 



31. DESCURAINIA. & Tansymustard 



Plants annual, stellate-pubescent and sometimes glandular; stems 

 often tall, leafy, simple or sparingly branched; leaves deeply pinnati- 

 fid or once to thrice pinnate, the segments mostly small; racemes ter- 

 minal, becoming elongate; flowers small, the petals yellow or whitish; 

 pods dehiscent, 2-celled, slender, elongate, terete or nearly so; seeds 

 many, small, in 1 or 2 rows in each cell. 



Some of the species are reported to be used by the Indians, both as 

 greens and for making pinole (gruel or mush), from the parched and 

 ground seeds. Among the Mexicans the seeds are used in poultices 

 for wounds. The plants grow mainly in open ground, flowering 

 chiefly in early spring. 



Key to the species 



1. Pods clavate or subclavate, spreading; upper leaves usually simply pinnate, 



the lower ones once or twice pinnate 1. D. pinnata. 



1. Pods not clavate, or somewhat so in D. obtusa var. brevisiliqua (2). 



2. Seeds in 2 rows in some or all of the pods; herbage canescent_ _ 2. D. obtusa. 

 2. Seeds in 1 row (3) . 



3. Leaves twice or thrice pinnate, with narrow segments; pods containing 20 



or more seeds, 10 to 30 mm. long 3. D. sophia. 



3. Leaves simply pinnate, the leaflets often deeply incised; pods often con- 

 taining fewer than 20 seeds (4) . 

 4. Pods 3 to 7 mm. long, attenuate at apex and tipped with the prominent 



style 4. D. californica. 



4. Pods 8 to 15 mm. long, not attenuate at apex, the style short or obsolete. 



5. D. RICHARDSONII. 



1. Descurainia pinnata (Walt.) Britton, Torrey Bot. Club Mem. 5: 

 173. 1894. 



Erysimum pinnatum Walt., Fl. Carol 174. 1788. 



Throughout the State, in several forms, the most abundant and 

 widely distributed species, up to 7,000 feet. Southeastern United 

 States to Mackenzie, south to Arizona, California, and northern 

 Mexico. 



52 Reference: Detling, Le Roy E. a revision of the north American species of descurainia. 

 Amer. Midland Nat. 22: 481-520. 1939. 



