A small endemic North American genus of 10 zerophytic species, differing from 

 Cleome (Sect. Peritoma) and Wislizenia in fruit characters. 



1. Seeds 3 to 6 per capsule; fruiting gynophore 6-17 mm. long; style 0.5 mm. long; 

 petals 4-6 mm. long; flowering portion of raceme short, flat or 



rounded, 1-2 cm. long; leaflets acute; eastern half of Texas 



I.e. angustifolia, 



1. Seeds 6 to 16 per capsule; fruiting gynophore 4-7 mm. long; style 1.5-2 mm. 

 long; petals 6-9 mm. long; flowering portion of raceme oblongoid- 

 elongate, 2-5 cm. long; leaflets often rounded to emarginate; Trans- 

 Pecos Texas 2. C. longipes. 



1. Cleomella angustifolia Torr. 



Glabrous erect often very bushy annual, 6-26 dm. tall; leaflets 3, linear-elliptic, 

 acute, 25-60 mm. long, 2-8 mm. wide; racemes to 4 dm. long, the flowering por- 

 tion flat to rounded and 1-2 cm. long, bracteate (the lower 3-foliolate, the upper 

 1-foliolate); petals yellow, 4-6 mm. long; mature capsules oblongoid to rhomboidal 

 or obdeltoid (cones acute to rounded), 5-10 mm. long, 5-9 mm. wide; style 0.5 

 mm. long or less; gynophore 4-7 mm. long, the androgynophore prominent and 

 1-1.5 mm. long; pedicel 7-12 (-17) mm. long; seeds 3 to 6 per capsule, dark- 

 brown-mottled. 



Deep sands, gravels in river bottoms, edge of ponds, roadsides, sandy prairies 

 and bare sandstone shale in e. half of Tex. (also Dawson Co.), June-Oct.; Tex. to 

 e. Kan., w. Neb. and n.e. Colo. 



2. Cleomella longipes Hook. 



Glabrous erect branched annual (or rarely perennial?) 3-8 dm. tall; leaflets 3, 

 oblanceolate to oblong-oblanceolate, acute to rounded or emarginate, 15-30 mm. 

 long, 4-10 mm. wide; racemes 1-5 dm. long, the flowering portion oblong-cylindric 

 and 2-6 cm. long; bracts 1-foliolate or upper flowers ebracteate; petals yellow, 

 6—9 mm. long; mature capsule (silicle) obdeltoid or rhomboidal (the cones often 

 sharply acuminate), 4-8 mm. long, 6-10 mm. wide; style 1-2 mm. long; gynophore 

 6-17 mm. long; pedicel 5-18 mm. long; seeds 6 to 16 per capsule, obovoid, when 

 mature dark-brown. 



In saline or alkaline soils or sands of semideserts, saline playas and wet soil on 

 alkali flats, in the Tex. Trans-Pecos, N.M. (Grant Co.) and Ariz. (Cochise Co.), 

 May-Sept.; s.e. Ariz., s.w. N.M. and w. Tex. to cen. Mex. 



3. Wislizenia Engelm. Jackass Clover 



About 3 species (or monotypic, with one highly polymorphic species ?) in 

 southwestern United States and northwest Mexico; very similar to Cleomella. 



1. Wislizenia refracta Engelm. 



Robust glabrous annual, 4-7 dm. high (easily confused with Cleomella spp.), 

 sparsely to densely branched; leaflets 3, oblanceolate to elliptic or ovate-oblong, 

 1-2 (-3) cm. long, 3-8 (-11) mm. wide, rounded at apex, attenuate at base into 

 slender petiolules to 4 mm. long; stipules minute tufts of filiform hairs; racemes 

 short, 1-8 cm. long, very dense, ebracteate; sepals minute, tardily deciduous; 

 corolla closed in bud; petals yellow, subsessile, 2-4 mm. long; stamens 6, 6-7 mm. 

 long, the anthers tightly coiled when dry; pistil long-exserted; style 4-6 mm. 

 long in fruit, very slender; gynophore slender, 3-7 mm. long, strongly refracted 

 against the slender pedicel (4-10 mm. long); fruit a 2-celled twin pod that 

 separates into 2 divaricate or deflexed obovoid nutlets, each with 1 or 2 seeds 

 permanently enclosed by the capsule-valve; nutlets 1.5-2.5 mm. long, smooth to 

 veined, minutely to markedly tuberculate at distal end; seed smooth, yellow. 



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