PEA FAMILY 525 



keel equalling the banner. Stamens partly diadelphous , i. e. , the tenth stamen 

 united with the rest at the middle, but free at the base. Legume flat, 1-2-seeded, 

 half-round, or spirally coiled, not jointed, pectinately prickly. 



1. O. Onobrychis (L.) Rydb. Perennial herb; stem erect, 3-5 dm. high; 

 leaflets 11-23, elliptic; calyx-lobes subulate, subequal; coroUa rose-colored, 

 striate; wings about half as long as the banner; legimne brown, obliquelj' semi- 

 orbicular, keeled above, the lower suture and apex with short broad prickle- 

 points. 0. sativa Lam. Cultivated and occasionally escaped: Mont. — Colo. — 

 L'tah — Ida. 



41. MEIBOMIA Heister. Tick-trefoil, Beggar's Ticks. 



Herbs (all ours), shrubs or vines. Leaves alternate, pinnately 3-foliolate, 

 rarely 1- or 5-foliolate; leaflets stipellate. Flowers perfect, in racemes or pan- 

 icles. Cal>T{ with bractlets at the base, campanulate; lobes unequal, the two 

 upper ones more or less imited. Corolla in ours reddish purple; banner more or 

 less clawed; wings oblique, more or less coherent with the keel. Stamens mon- 

 adelphous or partly diadelphous; anthers alike. Pod divided transversely into 

 several indehiscent internodes, flat, in ours retrorsely hispid. [Desmodium Desv.] 



Leaflets neither coriaceous nor strongly reticulate beneath. 1. M. canadensis. 



Leaflets coriaceous, strongly reticulate beneath. 2. M. illinoensis. 



1. M. canadensis (L.) Kuntze. Stem erect, 5-20 dm. high, pubescent; 

 leaflets elliptic or oblong-lanceolate, appressed-pubescent and paler beneath, 

 hispidulous or glabrate above; flowers paniculate, 11-17 mm. long, purple; loments 

 about 2.5 cm. long; internodes 3-5, somewhat triangular, straight or nearly so 

 on the upper suture, uncinate-pubescent. Desmodium canadense (L.) DC. 

 Thickets and river banks: N.B.—N.C.—Okla.— (Black HQls) S.D.— Man. 

 Plain— Suhmont. Jl-S. 



2. M. illinoensis (A. Gray) Kuntze. Stem 5-12 dm. high, uncinate- 

 pubescent; leaflets lanceolate or ovate-lanceolate, hispidulous above, cinereous 

 beneath, 2.5-9 cm. long; flowers paniculate, 6-9 mm. long, purple; loments 1-2.5 

 cm. long; internodes 3-6, oval or orbicular, densely uncinate. D. illinoense A. 

 Gray. Prairies: 111. — Kans. — S.D. Plain. Je-S. 



42. ViCIA L. Vetch, Wild Pea. 



Perennial or annual herbaceous vines. Leaves alternate, abruptly pinnate, 

 usually with tendrils or these represented by a tip. Flowers axillary, racemose 

 or sessile. Calyx somewhat oblique and gibbous at the base, the upper two 

 teeth shorter. Banner obovate or oblong, emarginate; wings obliquely oblong, 

 adherent to the curved keel. Stamens diadelphous (9 and 1); tube oblique at 

 the summit; anthers all alike. Style slender, with a tuft or ring of hairs at the 

 summit. Pod flat, dehiscent, 2-valved, few-- or several-seeded. 



Racemes .3— 40-flowered : flowers 1-2. .5 cm. long. 



Racemes one-sided, dense, 15-40-flowered. 1. V. cracca. 



Racemes lax, 3-10-flowered. 



Leaflets linear to oblong: stipules usually narrow, semi-sagittate and often entire. 

 Leaves decidedly pubescent, rather thick and strongly veined. 



Stem low; leaflets linear to oblong. 2. V. trifida. 



Stem tall; leaflets oblong or elliptic, only those of the lower leaves some- 

 times linear. 3. V. oregana. 

 Leaves glabrous or slightly pubescent when yotmg. 



Leaflets elongate, narrowly linear; plant low and erect. 4. V. sparsifolia. 

 Leaflets, at least the upper ones, oblong or linear-oblong; plant tall and 

 cUmbing. 5. V. dissitifoUa. 



Leaflets broad; stipiiles broadly semi-Sctgittate or semi-orbicular in outline, 

 sharply toothed. 

 Leaflets usually oval, thin and not strongly veined, mostly entire and acute 



or rounded at the apex. 6. V. americana. 



Leaflets obovate-cuneate, flrmer and more strongly veined, truncate and 

 toothed at the apex. 7. V. pumila. 



Racemes 1-2-flowered. 



Flowers 1-1.8 cm. long, subsessile in the axils; annual. 8. V. angusdfoHa. 



Flowers 6-8 mm. long, on a distinct peduncle; perennial. 9. V. producta. 



