224 LEGUMINOSAE. 



Sacramento and San Joaquin (T. amplectens T. & G.). Var. amplectens 

 forma tkincatum McDer. Very large; stems flaccid; leaflets and involucre 

 larger; inner whorl of flowers subtended by a very small involucral ring. — A 

 rich soil form of western California (T. truncatum Greene). 



3. T. tridentatum Lindl. Stems curving outward at the base in a whorl 

 of three or. more, % to 1% ft. high; leaves linear-oblong to lanceolate, Berrate- 

 setate to entire; heads hemispherical, broader than long, the flowers standing 

 out conspicuously, the wings protruding at right angles from the tube-like 

 whorl of the banner; divisions of the involucre very short; calyx-teeth 

 dilated, tridentate, shorter than the calyx-tube. 



Very common from the coast to the Sierra foothills, exhibiting many ecolog- 

 ical variations as included under the following varieties and forms: Forma 

 TRIMORPHUM McDer. Slender and more decumbent than the species; involucre 

 deeply cleft into unequal narrowly lanceolate lobes; calyx-teeth not always 

 tridentate. — Bay region and Sierra Nevada foothills (T. trimorphum Greene). 

 Var. segetum McDer. Tall, often 2 ft. high; stems hollow, 4 to 5 lines thick; 

 leaflets 2% in. long, 4 /f, in. wide; heads broadly conical; flowers large, the 

 tridentate calyx-teeth long, acicular. — The largest and most luxuriant variety, 

 abundant in the Bay region (T. segetum Greene). Var. aciculare McDer. 

 Erect; peduncles short; divisions of involucre unequal, long-acicular ; calyx- 

 teeth dilated, simple, becoming abruptly long-acicular. — Widely distributed 

 (T. aciculare Nutt.). Var. aciculare forma watsonii McDer. Very slender; 

 leaflets linear ; heads conical, involucre reduced ; calyx-teeth simple, the tip 

 ac ; cular, shorter than in the variety. — Range more restricted, Napa to Fresno 

 (T. watsonii Loja.). 



4. T. obtusiflorum Hook. Large and erect, hispidulous throughout; stems 

 hollow, clammy, 2 to 4 lines thick; leaflets large, obovate-oblanceolate or ob- 

 lanceelate, obtuse or acute, the margins remarkably fringed; peduncles 2% 

 in. long, axillary or dichotomously branched; heads large; involucre small; 

 calyx-teeth simple, dilated near base. 



Widely distributed throughout California but . rare as compared with its 

 relative T. tridentatum. The clamminess of the entire plant, even on dry 

 summer days, makes it easily recognizable. 



5. T. involucratum Ortega. Cow Clover. Strictly glabrous, low caes- 

 pitose (the numerous small leaves borne on a short stem) or tall; stems thick 

 but f'accid; petioles long; small leaflets obcordate or obtuse-oblanceolate ; 

 large leaflets obtuse-oblong or ovate, or rhombic-oblanceolate, the margins 

 serrulate setate ; heads large, show r y, the flowers purple, rose-red or pinkish, 

 lighter at the top; involucre deeply or slightly lobed, each lobe 3 to 5-toothed; 

 ralvx in nerved; pod 2 to 6-seeded. — (T. wormskjoldii Lehm.) 



Frequent along streams, by springs or in salt-marshes. Apr. -dune. 



6. T. appendiculatum Loja. Glabrous; stems erect, thick and fistulous; 

 stipules retlexed or spreading, irregularly laciniate: Leaflets rhombic, obtuse- 

 obovate or broadly oblanceolate; involucre 7 to 9-lobed, the lobes 3 to 5-toothed; 



heads large, showy; (lowers dark purple, cream-tipped; beak of keel long 



apiculate. 



Mendocino Co. and Pacific Grove. Rare. Forma rostratum McDer. 

 Dwarf, about 1 in. high; leaflets small, olicordate, on long filiform petioles; 



involucre -llol.ed, each lobe :'» to » toothed; heads small, few flowered ; keel 

 rostrate. Marin and Alameda cos. (T. rostratum Greene.) May-June. 



7. T. variegatum Nutt. Whitk tip ( i.oykk. Strictly glabrous, decumbent 



