574 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



1. Malvastrum bicuspidatum (S. Wats.) Rose, Contrib. U. S. Natl. 



Herbarium 12: 286. 1909. 



Malvastrum tricuspidatum var. biscuspidatum S. Wats., Amer. 

 Acad. Arts and Sci. Proc. 21: 417. 1886. 



Pinal and Pima Counties, 4,000 to 5,000 feet, occasional on rocky 

 slopes, April to October. Southern Arizona and Mexico. 



Closely related to the South American M. scabrum (Cav.) A. Gray 

 and M. scoparium (L'Her.) A. Gray. The Arizona plant was referred 

 by Gray to the latter species. 



2. Malvastrum rotundifolium A. Gray, Amer. Acad. Arts and Sci. 



Proc. 7: 333. 1868. 



Eremalche rotundijolia Greene, Leaflets 1: 208. 1906. 



Yuma and Mohave Counties, 100 to 1,500 feet, not infrequent in 

 dry, sandy soil, often in washes, March to April. Western Arizona, 

 southern California, and southern Nevada. 



A showy plant when in flower. 



3. Malvastrum exile A. Gray in Ives, Colo. Riv. Rpt. 8. 1860. 



Eremalche exilis Greene, Leaflets 1: 208. 1906. 



Mohave, Pinal, Maricopa, Pima, and Yuma Counties, up to 3,500 

 feet, common at roadsides and in fields, February to May, type from 

 Pyramid Canyon, Mohave County (Newberry in 1858). Southwestern 

 Utah to southern Arizona and California. 



Reported to be used as food by the Pima Indians, in times of 

 scarcity. The plant affords considerable grazing in southern Arizona, 

 in early spring. 



8. SIDA 



Plants mostly perennial, herbaceous or suflrutescent, more or less 

 pubescent with forked, stellate, or scalelike hairs; flowers axillary, 

 solitary or in small cymules, these sometimes assembled in terminal 

 leafy panicles; involucel usually none; carpels indehiscent or dehiscent 

 only part way from the apex, more or less rugose and often reticulate 

 on the sides. 



Key to the species 



1. Calyx greatly enlarged in fruit, papery, veiny, the segments appearing cordate 

 at base; taproot long, tuberlike, often fusiform; stems and leaves hispid 

 (usually sparsely so) with long, mostly few-rayed hairs; petals not or 



scarcely surpassing the calyx 1. S. hastata. 



1. Calyx not or bat slightly enlarged in fruit, not papery or veiny, the segments 



not appearing cordate; taproot sometimes stout but not tuberlike or 



fusiform; stems and leaves puberulent, canescent, or lepidote (if long 



hairs also present, these simple, not stiff) ; petals considerably surpassing 



the calyx (2) . 



2. Flowering stems from elongate rootstocks, decumbent or prostrate; plants 



conspicuously whitish stellate-canescent or lepidote; leaf blades very 



oblique at base; petals 10 to 20 mm. long, white or ochroleucous when 



fresh, often fading pink; peduncles axillary, mostly 1-flowered, commonly 



decurved or sigmoid after anthesis; carpels reticulate on the sides, 



muticous or nearly so (3). 



3. Stems and leaves densely whitish canescent with short, stellate 



hairs; leaf blades broadly deltoid or suborbicular, wider than long, 



rounded at apex, rather regularly dentate; involucel of 1 to 3 subulate 



bractlets, usually persistent until or after anthesis; petals ochroleucous 



when fresh; carpels indehiscent 2. S. hederacea. 



