LEGUMINOSAE (PEA FAMILY) 299 



Calyx and spike densely silky-villous 3. P. compactus. 



Flowers not white. 

 Leaflets 5-9. 



Glands evident 4. P. purpureus. 



Glands wanting or obscure . . . . . . . . 5. P. pubescens. 



Leaflets 13-17 6. P. villosus. 



1. Petalostemon candidus Michx. Fl. Bor. Am. 2: 49. 1803. Glabrous; 

 stems firm and erect, sparingly branched : leaflets 7 or 9, lanceolate or linear- 

 oblong, sparingly dotted beneath: spikes oblong, in age long-cylindrical: calyx 

 glabrate: corolla white; wing and keel petals ovate; the standard broadly 

 cordate: ovary pubescent. Coming into our range from the prairie states. 



2. Petalostemon oligophyllus (Torr.) Rydb. Mem. N. Y. Bot. Card. 

 1: 237. 1900. Very similar but the stems slender, ascending, freely branched: 

 leaflets 5-9, linear-oblong: spike short, ovate-oblong, becoming cylindric, 

 loosely flowered. Very common; from Montana to Texas. 



3. Petalostemon compactus (Spreng.) Swezey, Nebr. Fl. PI. 6. 1891. 

 Glabrous; stem sparingly branched, 3-6 dm. high, dotted: leaflets 5-7, 

 lanceolate-oblong, obtuse, dotted beneath: spikes cylindrical, very dense and 

 much elongated; bracts lanceolate, as long as the flower: calyx silky-villous; 

 the teeth lanceolate: standard cordate; the other petals linear-oblong, all 

 white or nearly so. P. macrostachyus. Throughout the eastern part of our 

 range. 



4. Petalostemon purpureus (Vent.) Rydb. 1. c. Smooth or nearly so: 

 leaflets 5, narrowly linear: spikes globose-ovate, or oblong-cylindrical when 

 old; bracts pointed, not longer than the silky-hoary calyx: corolla rose-purple. 

 P. violaccus. Prairies from the Saskatchewan to Texas, and from Colorado 

 to Indiana. 



4a. Petalostemon purpureus mollis (Rydb.) A. Nels. Stems and leaves 

 more or less villous-pubescent: leaflets linear, usually obtusish: corolla rose- 

 color. (P. mollis Rydb. Mem. X. Y. Hot. Card. 1: 238. 1900.) Probably 

 '. tenuifolius Gray as to our range. Montana to Colorado. 



5. Petalostemon pubescens A. Xels. Bot. Gaz. 31: 395. 1901. Pale with a 

 iblanate pubescence throughout: stems several-many from a large woody 



crown, from suberect to prostrate-assurgent, 1-3 dm. long: leaves neither 

 glandular nor dotted, 5-foliolate; the leaflets spatulate-linear, obtuse, 10-14 

 mm. long: spike oblong, dense, silvery-lanate; bracts about as long as the ca- 

 lyx, obovate, abruptly acuminate, the purple tip concealed by the copious pu- 

 bescence: corolla light purple. Southern Colorado. 



6. Petalostemon villosus Xutt. Gen. 2: 85. 1818. Soft-downy or silky 

 all over: leaflets 13-17, linear or oblong, 8-10 mm. long: spikes cylindrical, 

 3-10 cm. long, short-peduncled, soft-villous; bracts lanceolate, acuminate, 

 exceeding the calyx: corolla rose-purple, often pale; standard oblong; the 

 wings and keel oblong-obovate. Xortheastern part of our range to Wiscon- 

 sin and Missouri. 



16. HEDYSARUM L. 



Perennial herbs. Leaves odd-pinnate. Calyx 5-cleft, the lobes awl-shaped 

 and nearly equal. Keel nearly straight, obliquely truncate, not appenda^ed, 

 longer than the wings. Stamens diadelphous (9 and 1). Pod flattened, com- 

 posed of several equal-sided, separable, roundish joints connected in the middle. 



Flowers rose-color, lilac, or purple. 



Stems and leaves canescent . . . . . . . .1. H. cinerascens. 



Steins and leaves green, glabrate or obscurely pubescent. 



Joints of loment wing-margined . . . . . . 2. H. marginatum. 



Joints of loment not wing-margined. 



Flowers tardily if at all reflexed 3. H. pabulare. 



Flowers reflexed from the first 4. H. uintahense. 



Flowers white or yellow. 



Leaflets 11-13 5. H. sulphurescens. 



Leaflets 15-23 6. H. philoscia. 



1. Hedysarum cinerascens Rydb. Mem. N. Y. Bot. Gard. 1: 257. 1900. 

 Cinereous-canescent: stems several, erect or decumbent, 3-6 dm. high: leaflets 



