298 LEGUMINOSAE (PEA FAMILY) 



strongly dotted: spikes panicled, few-flowered; flowers distant; bracts very 

 broad, almost orbicular, glandular, coriaceous, glabrous, slightly cuspidate, 

 embracing the flower: calyx deeply cleft, teeth long, setaceous, beautifully 

 plumose: corolla white, keel twice as long as the wings; standard cordate, very 

 small, sometimes with 4 approximated glands near the middle. Texas to 

 Colorado and the upper Missouri. 



3. Parosela formosa (Gray) Vail, Bull. Torr. Bot. Club 24: 16. 1897. 

 Suffruticose, much branched: leaflets very small, about 5 pairs, cuneate- 

 oblong, retuse, dotted with black glands beneath: spikes loose, few-flowered, 

 on short peduncles; flowers large and showy, bright purple; bracts ovate, 

 silky-villous on the margin. On the Platte and southward. 



4. Parosela Jamesii (Torr.) Vail, 1. c. Whole plant silky; stems several, 

 8-15 cm. high: leaves trifoliolate, glandless; the leaflets obovate, very obtuse; 

 stipules spiny: spikes oblong, dense, 2-3 cm. long: calyx deeply cleft, the seg- 

 ments setaceous-plumose: keel and wings oblong, purple, the standard yel- 

 lowish: bracts rhombic-ovate, as long as the calyx. Colorado and southeast- 

 ward. 



5. Parosela Porteri A. Nels. Bot. Gaz. 31: 395. 1901. Stems several or 

 many, prostrate-spreading from the crown of a woody root, 10-25 cm. long: 

 leaves trifoliolate, strigose-silky; the leaflets cuneately obovate; stipules se- 

 taceous: spike dense, 2-5 cm. long, with purple bracts: calyx-tube campan- 

 ulate, with 10 greenish nerves; the triangular lobes attenuate into filiform 

 plumose setae twice as long as the tube: flowers lemon-yellow: keel and wings 

 oval or broader; the standard shorter than the wings, broader than it is long. 

 Berwind, southern Colorado. 



6. Parosela aurea (Nutt.) Brit. 1. c. Stems pubescent, simple, erect, 

 4-8 dm. high: leaflets 3-4 pairs, oblong-ob ovate and linear-oblong, more or 

 less silky-pubescent: spikes ovate, very compact, on long peduncles; bracts 

 rhombic-ovate, as long as the calyx: corolla yellow, 8-10 mm. long; the stand- 

 ard much shorter than the wings and keel. From the eastern border of our 

 range to Missouri and Texas. 



7. Parosela rubescens Wats. Proc. Am. Acad. 17: 369. 1882. Stems 

 2-4 dm. high, canescent with appressed pubescence, branching; branches 

 leafy to the top: leaves remote; leaflets 2-3 pairs, oblong and obovate, slightly 

 apiculate, clothed with silky, canescent hairs, not dotted, 3-8 mm. long: 

 spikes ovate, loosely flowered, elongated and cylindrical in fruit, 2 mm. long; 

 bracts obovate, apiculate, about the length of the yellow flowers (purplish in 

 drying) : calyx deeply cleft, teeth setaceous, plumose. Southeastern Colorado 

 and southward. 



8. Parosela lanata (Spreng.) Brit. 1. c. Decumbent, the whole plant 

 clothed with a soft almost woolly pubescence: leaflets 4-6 pairs, obovate- 

 cuneate, emarginate, 10-12 mm. long: spikes elongated, rather loose, many- 

 flowered, on rather long peduncles; bracts ovate, with a long acumination : 

 calyx-teeth subulate, plumose, dilated at base, as long as the tube: petals 

 deep purple. Southern part of our range and southward. . 



15. PETALOSTEMON. PRAIRIE CLOVER 



Herbaceous, mostly perennial plants, dotted with glands. Leaves unequally 

 pinnate; stipules minute, setaceous. Flowers in pedunculate, dense, terminal 

 spikes or heads. Calyx often glandular, 5-toothed; the teeth connivent, nearly 

 equal. Petals 5, on filiform claws; four of them nearly similar, their claws 

 united to the stamen-tube quite to the summit and deciduous by an articu- 

 lation; the standard free, inserted at the bottom of the calyx; the limb cor- 

 date or oblong, conduplicate. Stamens 5, monadelphous; the tube cleft. 

 Ovary with 2 collateral ovules. Pod membranaceous, inclosed in the calyx, 

 indehiscent, 1 -seeded. 



Flowers white. 



Calyx and spike glabrate. 



Leaves lanceolate or oblong . .... . . 1. P. candidus. 



Leaves linear or nearly so . , , , . , . 2. P. oligophyllus, 



