FABACEAE 631 



12. Petalostemon Sabinalis S. Wats. Plant glabrous, yellowish green. Stems 

 branched at the base, the branches ascending, 2-4 dm. long, commonly simple : leaflets 

 11-15, the blades linear or sliglitly broadened upward, 10-15 mm. long, nearly flat, gland- 

 ular-dotted beneath, blunt : spikes cylindric, 4-6 cm. long, about 1 cm. thick, excluding 

 the corollas, peduncled : bracts about as long as the calyxes, deciduous : calyx glabrous 

 without, about 3 mm. long; tube ribbed at maturity; lobes triangular, shorter than the 

 tube : corolla rose-colored ; standard notched at the apex, the other petals obtuse. 



On dry plains or prairies, Texas. Spring and summer. 



13. Petalostemon piirpureua (Vent.) Rydb. Plant glabrous or sparingly pubes- 

 cent. Stems often tufted, erect or ascending, 3-9 dm. tall, more or less branched above : 

 leaflets 3-5, the blades narrowly linear, S-20 mm. long, acute, strongly involute : spikes 

 oval to cylindric, 1.5-5 cm. long: bracts oblanceolate, abruptly acuminate : calyx silky, 

 usually surpassing the bract ; tube cainpannlate ; lobes triangular, much shorter than the 

 tube :' corolla violet or purple ; standard with a dilated blade cordate or subcordate at the 

 base. IPetalostemoii violaceus Michx.] 



On prairies, Northwest Territory to Minnesota, Indiana, Texas and Colorado. Summer. 



14. Petalostemon Porterlknua Small. Plant sparingly pubescent, but the upper 



Earts, at least, tawny-pubescent. Stems 2-3 dm. tall, or sometimes taller, more or less 

 ranched : leaflets 3-5, the blades nearly linear, 8-14 mm. long, strongly involute : spikes 

 oblong or cylindric, 1.5-2 cm. long : bracts surpassing the buds : calyx villous ; tube promi- 

 nently ribbed ; lobes shorter than the tube : corolla violet-purple. 

 On prairies, Arkansas. Summer. 



15. Petalostemon tenuifolius A. Gray. Plant somewhat pubescent. Stems usually 

 branched at the base, with erect or ascending branches, 1.5-3 dm. tall, pale : leaflets 3-5, 

 the blades linear to linear-spatulate, 8-18 mm. long, involute, blunt, sparingly glandular: 

 spikes cylindric, 2-4 cm. long, barely 1 cm. thick : bracts rather abruptly contracted into 

 slender subulate tips : calyx silky-villous like the bracts, becoming about 4 mm. long : 

 lobes triangular-lanceolate, about as long as the tube : petals rose-colored ; standard with 

 a cordate hooded blade. 



On plains or prairies, Arkansas to Arizona. Summer. 



16. Petalostemon Gattingerl Heller. Plant sparingly pilose or glabrous below. 

 Stems usually several together, 2-5 dm. long, ascending or decumbent, simple or much 

 branched : leaflets 5-7, the blades narrowly linear or linear-oblong, 1-2 cm. long, glandu- 

 lar, slender at the base : spikes cylindric, 3-10 cm. long : bract oval-lanceolate with sub- 

 ulate tips, pubescent : calyx villous-pilose, shorter than the bract ; tube campanulate, 

 ribbed ; lobes lanceolate or triangular-lanceolate, acute : corolla rose-purple ; standard 

 with a broad blade truncate or cordate at the base. 



On rocky barrens and in cedar glades, Tennessee. Spring and summer. 



17. Petalostemon Reverchonii S. Wats. Plant bright green. Stems branched 

 at the base, the branches more or less diffuse, 1-2 dm. long, finely pubescent : leaflets 

 glabrous, 5-11, the blades linear or linear-oblanceolate, 7-10 mm. long, acutish, somewhat 

 involute : spikes subglobose or oblong-globose, 1-1.5 cm. long, becoming 4-7 cm. long at 

 maturity, about 1 cm. thick : rachis tomentulose : bracts mostly shorter than the calyxes, 

 deciduous : calyx about 4 mm. long, silky-villous ; lobes acute or acuminate : corolla red 

 or deep pink. 



On the summit of Comanche Peak, Texas. Spring and summer. 



18. Petalostemon pub6acens (A. Gray) Heller. Plant glaucous. Stems usually 

 several together, erect or ascending, 3-7 dm. tall, simple or nearly so : leaflets 3-7, the 

 blades linear, 10-14 mm. long, acute, glandular beneath, involute, slender-stalked : spikes 

 oblong or oval, 2-4 cm. long : bracts broadly ovate, short-tipped : calyx surpassing the 

 bract ; tube campanulate, glabrate ; lobes triangular-lanceolate, acuminate, silvery pubes- 

 cent : corolla rose-purple ; standard with a cordate or subcordate blade. 



In dry soil, Texas. Spring and summer. 



19. Petalostemon Stanfifeldii Small. Plant glabrous to the inflorescence. Stems 

 tufted, 1-3 dm. tall, often branched near the base, the peduncles or most of them slightly 

 shorter than the leafy stem : leaflets 3-5, the blades linear or narrowly linear-spatu- 

 late, 5-12 mm. long, acute, strongly involute : spikes cylindric or oblong-cylindric, 1-2.6 

 cm. long, less than 1 cm. thick : calyx puberulent ; lobes triangular, about one-half as 

 long as the tube : corolla rose-purple ; standard with a broad cordate or subcordate blade. 



On plains or prairies, Texas. Summer. 



20. Petalostemon t6nviis (Coulter) Heller. Plant nearly glabrous below the in- 

 florescence. Stems 3-4 dm. tall, relatively slender, somewhat glaucous, branched : leaf- 



