96 LEGUMINOS.E. 



8. T. dichotomum, Hook. & Am. Erect or ascending, stoutish, 

 1 — 1)4 ft- high, often flexuous and repeatedly dichotomous: pubescence 

 longer than in the last, more spreading: leaflets cuneate-obovate or 

 oblanceolate, the upper acute, % in. long, sharply denticulate: heads 

 long-peduncled, ovate-conical % — 1)4 in. high: calyx-teeth setaceous, 

 densely hairy, equalling the red-purple corolla: pod with close elevated 

 striae. — Plentiful on plains of interior, from Vacaville to Antioch. 



9. T. amoenmn, Greene. Commonly 2 ft. high, stout, simple or with 

 few branches from the base, the heads 1 — 3, terminal and subterminal, 

 herbage canescently villous: leaflets broadly obovate, retuse or obtuse, 

 erose-denticulate, 1 in. long or more, 10 lines broad: heads globose, in age 

 oval 1% i n - high: calyx-teeth linear-setaceous, plumose throughout, 3 — 4 

 lines long, much shorter than the very showy corolla; this light rose- 

 purple with dark centre. — Vanden Station, Sacramento plains. 



10. T. columbinum, Greene. Erect, nearly simple, 1 ft. high, some- 

 what silky-pubescent: leaflets 1 in. long, cuneate-oblong, obtuse, 

 crenulate-denticulate : head ovate-conical, 1 in. high: calyx-tube less than 

 1 line long; the filiform segments 5 lines, soft and silky-plumose throughout, 

 deeply concealing the minute purple corolla: pod striate, villous at 

 apex. — Common about Vacaville; readily known by its pale dove-colored 

 heads altogether soft and silky, exhibiting no flowers, but seemingly 

 made up of the long, densely plumose calyx-teeth. May. 



11. T. olivaceum, Greene. Simple or branched from the base, 1 — \% 

 ft. high, glabrous except an appressed pubescence on the lower face of 

 the leaves: petioles 1 — 2 in. long, with lanceolate acuminate entire 

 stipules; leaflets as in the last, but somewhat serrulate: heads on long 

 slender peduncles, hemispherical in flower, 1 in. or more broad and high; 

 calyx-tube 1 line long; the linear-setaceous teeth 6 — 6 lines, densely plumose 

 toward the base only, gradually less so above, nearly naked at the rather 

 rigidly setaceous tips; corolla deep violet-purple, very small and con- 

 cealed; pod striate, glabrous. — With the preceding, but more common; 

 distinguished by its large olive-green heads. 



12. T. arvbnsb, L. Belated to the last two, but of different aspect; 

 the numerous branches lateral, not basal; the leaves and heads short- 

 stalked: heads oblong or cylindrical, % in. long, or less: calyx-teeth 

 silky-plumose throughout, longer than the minute 'whitish corolla. — The 

 Rabbit-foot or Mouse-ear Clover of Europe, naturalized on the Atlantic 

 coast, has been reported from Alameda Co. 



* * Heads subtended by a flat or concave (sometimes nearly obsolete) 



involucre. 



■i— Corolla not inflated in age. 



+-^Involucre flat; heads a little one-sided. 



13. T. Wormskjoldii, Lehm. Perennial, spreading underground by 

 slender root-stocks; stems decumbent, 3 in. — 2 ft. long; herbage flaccid, 



