318 LEGUMINOSilS. Trifolium. 



Leaflets an inch or more in Icns^th, conspicuously frinsrcd with spinulose-se- 

 tactous teeth. Heads an inch in diameter. Teeth of the calyx shorter than 

 the tube, unequal, spiny. Corolla slender, purple. Legume 2-seeded. — We 

 have only examined cultivated specimens : in these the leaflets are ahnost 

 lanceolate or oblanceolate. 



24. T. spinulosum (Dougl.): prostrate, clahrous; leaflets cblong, acute at 

 each end, spinulose-denticulate, terminated by a rigid spiny point ; stipules 

 ovate, acuminate, sninulose-serrate; involucre laciniately many-cleft, shorter 

 than the subglobo>e heads ; teeth of the calyx narrowly subulate, pungent, 

 straight, a little shorter than the corolla (corolla white, the keel and wings 

 tipped with fine purple). — Hook. ^ft. Bor.-Am. 1. p. 133. 



li. triste: leaflets oblong-cunclform ; corolla duU purple. — T. triste, Awi^ / 

 mss. 



Oregon, "near springs, in mountain vallies, forming a dense short sward ; 

 the herbage preferred to everything else by deer and horses." Douglas., in 

 Hook. p. St. Barbara, California, Nuttall ! — Smaller and more slender 

 than the preceding species. Teeth of the calyx 3 or 4 times the length of 

 the tube, setaceous. Legume 2-seeded. 



25. T. heterodon : decumbent, glabrous ; leaflets oblong or oval, some- 

 what cuneiform at the base, mucronalely ciliate-serrulate, obtuse, the lowermost 

 mostly emarginate ; stipules membranaceous, ovate, acuminate, laciniately 

 serrate with subulate teeth, the lov/er ones lanceolate and often nearly entire; 

 involucre laciniately many-cleft, much shorter than the (large) hemispherical 

 head ; teeth of the calyx narrowly subulate, nearly equal, longer than the tube, 

 much shorter than the corolla ; legume 3-6-seeded. 



a. teeth of the calyx entire ; the two upper ones united a little highest. — T. 

 atropurpureum, Niiit.! mss. 



3. lower teeth of the calyx setaceously 2-3-cleft. T. calocephalum, Nutt.! 

 mss. 



J/, teeth of the calyx usually all deeply and unequally 2-3-cleft; the seg- 

 ments setaceous. 



Oregon and California, a. Borders of m.arthes near the mouth of the 

 Oregon, Nuttall! Dr. Seoul er ! 0. St. Barbara, Douglas! Nuttall! y. 

 California, Douglas ! June. — 11 Stems several from one root, 10-18 inches 

 long, simple or a little branching, usually producing only terminal heads. 

 Leaflets ^-1 inch in length, very finely and sharply serrulate. Heads an inch, 

 or a little more, in diameter, depressed, on slender peduncles. Flowers large, 

 rather dark purple ; the vexillum paler at ihe tip. Calyx-teeth a little spread- 

 ino-. Ovary somewhat stipitate. — We have long possessed specimens of this 

 species collected by Dr. Scouler (as v^'dl as the various forms from Doug- 

 las's collection), but we do not find it described in Hooker's Flora. 



26. T. involucratum (Willd.): nearly erect, glabrous; leaflets narrowly 

 linear-lanceolate, mucronate, spinulosely serrulate; stipules mcmbiaracec us, 

 cblong-ovate, aristate, the ujiper onespectinately dentate with setaceous teeth, 

 the lowermost narrower and nearly entire ; involucre laciniately many-cleft, 

 a little shorter than the rather loose subhemispherical heads; teelh of the 

 calyx much shorter than the tube, subulate from a very broad base, pungent, 

 entire or often 1-toothed at the base on each side, a little shorter than the 

 corolla; legume dehiscent, 1-2-seedeA.— Willd. sp. 3. p. 1372?; Sviith. in 

 Rees, cycl; Hook.! ft. Bor.-Am. 1. p. 133, not ot Kuvth, ^ DC. T. "S^'ill- 

 denovii, Spreng. syst. 3. p. 208 ? T. tridentatum, Lindl. bot. reg. sub t. 

 1070. 



/?. leaflets of the lower leaves linear, entire. 



Dry gravelly soils, CaUfornia, Menzies, Douglas ! and from the mouth of 

 the Oregon to the Rocky Mountains, Douglas^ Nuttall! — (T) Plant slender, 

 br:inching from the base, the divisions 10-18 inches high, slender, scarcely 



