STRBPTANTHOID GENERA. 235 



belong to the arid interior ; the species of one of them ranging 

 between Arizona and Texas, not far to the northward of the 

 Mexican boundary ; those of another, far more numerous, occur 

 at many different stations all the way between the Kocky Moun- 

 tains of Colorado and Wyoming on the one hand, to the Cas- 

 cades and Sierra Kevada on the other. A third is typically 

 Californian. 



The genus of altogether southerly range I name 



DiSACCANTHTJS. Calyx of thin texture, but not as in EucUsia, 

 inflated in the middle and closed at the summit, two larger sepals 

 distended at base and saccate. Pods broad and flat ; seeds broad 

 thin, wing-margined. Plants of a thinnish foliage, the basal 

 leares (early disappearing) runcinate-pinnatifid, and forming a 

 rosulate tuft, the cauline cordate-amplexicaul. 



The few species may take names as follows : 



D. CARiNATUS. Streptanfhus carinatus, C. Wright. Calyx 

 purple, all four sepals saccate, and more notably so than in other 

 species. Pods 2i inches long, 3 lines wide. — The original from 

 a cafion 60 miles below El Paso, Texas. 



D. VALiDUS. Plant stout, rigid, with few rigidly ascending 

 branches: pods oblong-linear, very large. If -3 inches long, fully 

 4 lines wide, obtuse. — Type from somewhere in western Texas, 

 1884, by M. E. Jones, who mistook it for Streptanthus platy- 

 carpus. Gray. 



D. MoGOLLONicus. Calyx very thin, creamy white, sepals less 

 notably saccate : pods 3 inches long, barely a line wide. — Type 

 collected by myself among foothills of the Mogollones in New 

 Mexico, 30 March, 1881. All white-flowered material from New 

 Mexico from Las Cruces to the upper Gila belongs here. 



D. LTJTBUS. Elowers wholly of a clear yellow. — A more north- 

 erly species, of the Black Eange, New Mexico, known only in 

 flowering specimens collected in 1905 by 0. B. Metcalfe. 



D. Akizonicus. Strepianthus ArizonicuSjWatB. Plant more 

 delicate than in other species; no rosula if basal leaves; stem 

 slender, simple ; flowers nearly white. — Mountains of southern 

 Arizona. 



