GENUS 19. 



PEA FAMILY. 



i. Petalostemum compactum (Spreng.) 

 Swezey. Dense-flowered Prairie- 

 clover. Fig. 2512. 



Dalea compacta Spreng. Syst. Veg. 3 : 327. 1826. 

 Petalostemon macrostachyus Torr. Ann. Lye. 2: 176. 



1828. 



P. compactus Swezey, Nebraska Flow. PI. 6. 1891. 

 Kulinistera compacta Kuntze, Rev. Gen. PI. 192. 1891. 



Erect, dotted with sessile glands, branched, i-2-J 

 high. Leaflets 5-7, glabrous, short-stalked, oblong- 

 lanceolate or linear-oblong, acute or obtusish, dotted 

 beneath, 6"-i2" long, about 2" wide; peduncles ter- 

 minal, elongated, not bracted ; spikes cylindric, 2-6' 

 long, about 6" thick, the rachis pubescent ; flowers 

 white or nearly so, about 2" long; bracts awn- 

 pointed, longer than the densely villous-pubescent 

 calyx ; wings and keel-petals oblong ; standard cor- 

 date ; pod pubescent, enclosed by the calyx. 



In dry soil, South Dakota to Nebraska, Kansas, 

 Colorado and Wyoming. July-Aug. 



2. Petalostemum candidum (Willd.) 



Michx. White Prairie-clover. 



Fig. 2513. 



Dalea Candida Willd. Sp. PI. 3: 1337. 1803. 

 P. candidum Michx. Fl. Bor. Am. 2 : 49. 1803. 

 Kuhnistera Candida Kuntze, Rev. Gen. PI. 192. 

 1891. 



Glabrous, stems erect, assurgent, or rarely 

 prostrate, simple, or sparingly branched, i-2 

 high. Leaves petioled; leaflets 5-9, oblong, or 

 oblanceolate, 8"-i2" long, \\"-$' wide, obtusish 

 or acuie^qsid often mucronulate at the apex, 

 narrowed at the base, very short-stalked ; pe- 

 duncles terminal, elongated, bracted ; spikes 

 cylindric, i'-4' long, s"-6" thick; bracts awn- 

 pointed, longer than the calyx ; corolla white, 

 2"-3" long; wings and keel-petals oval;. stand- 

 ard cordate; calyx-teeth and pod slightly pu- 

 bescent. 



Prairies and plains, Indiana to Minnesota, 

 Manitoba, Tennessee, Louisiana, Texas and Colo- 

 rado. June-Aug. White tassel-flower. 



3. Petalostemum oligophyllum Torr. 

 Slender White Prairie-clover. Fig. 2514. 



Petalostemon gracile var. oligophyllum Torr. Em- 

 ory's Mil. Rec. 139. 1848. 



Kuhnistera Candida var. occidentalis Rydberg, Contr. 

 Nat. Herb. 3: 154. 1895- 



Kuhnistera oligophylla Heller, Bull. Torr. Club 23: 

 122. 1896. 



Petalostemon oligophyllum Torr. ; Smyth, Trans. 

 Kans. Acad. 15: 61. 1898. 



Glabrous, stem slender, erect or ascending, usu- 

 ally_ much branched, i-2-J tall, the branches 

 straight, ascending. Leaves short-petioled ; leaf- 

 lets about 7 (5-9), linear, linear-oblong or some- 

 what _ oblanceolate, firm, varying from less than 

 I wide to 2" wide, mostly less than 10" long, 

 or those of the lower leaves larger ; spikes oblong 

 or short-cylindric, blunt ; bracts lanceolate, acu- 

 minate, equalling the calyx, or longer, deciduous ; 

 calyx-teeth usually pubescent; corolla white. 



Plains, South Dakota to Nebraska, Wyoming, 

 Texas, Arizona and Mexico. Root sometimes over 

 i long. June-Sept. 



2 4 



