PEA FAMILY 535 



Trifolium trilobitum Jepson, Bull. Torrey Club 18: 322. 1891. (T. calophyllum Greene, T. phaeocepha- 

 lum Greene). Probably only a color form of T. melananthum Hook. & Arn. from which it is best distinguished 

 by the yellow-tipped or lilac-tipped petals. Foothills of the Sierra Nevada from Siskiyou County to Kern County, 

 California. 



45. Trifolium polyodon Greene. Monterey Clover. Fig. 2700. 



Trifolium polyodon Greene, Pittonia 3: 215. 1897. 



Annual, glabrous, the stems 3-4 dm. long, nearly prostrate. Leaves, at least the lower, long- 

 petioled, stipules laciniate with reflexed margins; leaflets 1-2 cm. long, obovate, serrulate; in- 

 volucre shallowly lobed, each lobe many-toothed; heads 8-15 mm. broad; calyx-tube turbinate, 

 10-nerved, the teeth 3- to several-toothed ; corolla 8-10 mm. long, purple, the tips lighter fading 

 to white ; pods 2-seeded. 



Moist places, Humid Transition Zone; Monterey Peninsula, California. May-June. 



46. Trifolium variegatum Nutt. White-tipped Clover. Fig. 2701. 



Trifolium variegatum Nutt. in Torr. & Gray, Fl. N. Amer. 1: 317. 1838. 



Annual, glabrous, the stems usually several from the base, decumbent or ascending, 2-6 dm. 

 long. Stipules ovate, laciniately toothed ; leaflets variable, those of the lower leaves small, mostly 

 cuneate, obcordate, those of the upper obovate or oblong-lanceolate, 5-15 mm. long, setose- 

 serrulate; peduncles slender, exceeding the leaves; heads obliquely subglobose, 6-12 mm. broad; 

 involucre lobed and laciniately toothed, narrower than the heads ; calyx-teeth subulate-setaceous, 

 longer than the tube, simple or one tooth bifid; corolla purple, white-tipped, 6-8 mm. long; 

 pod 2-seeded. 



Moist places, Transition and Upper Sonoran Zones; British Columbia to southern California. Type locality: 

 springy places near the mouth of the Willamette River, Oregon. May-July. A variable species of which the 

 following is one of the extreme forms. 



Trifolium geminiflorum Greene, Pittonia 3: 216. 1897 (7\ pusillum Greene, T. dianthum Greene). An- 

 nual, glabrous, branches slender, S-2S cm. long; leaflets obcordate to oblanceolate, 8-10 mm. long; peduncles 

 almost filiform; involucre one- to few-lobed; heads small, usually 2-5-flowered; corolla about 6 mm. long, light 

 purple with whitish tips. Mountain springs and streams, Transition and Canadian Zones; southern Oregon to 

 southern California. 



47. Trifolium tridentatum Lindl. Tomcat Clover. Fig. 2702. 



Trifolium tridentatum Lindl. Bot. Reg. 13: under pi. 1070. 1827. 

 Trifolium segetum Greene, Pittonia 3: 221. 1897. 

 Trifolium trimorphum Greene, Pittonia 3: 220. 1897. 



Annual, glabrous throughout, the stems erect, or somewhat decumbent, often branching from 

 the base, 2-5 dm. high, more or less branched above. Lower stipules lanceolate-acuminate, en- 

 tire, the upper shorter and laciniate; leaflets oblong-lanceolate to narrowly linear-lanceolate, 

 15-35 mm. long, more or less setaceously toothed ; peduncles axillary, elongated ; heads mostly 

 15-20 mm. broad; involucre a flat disk, unevenly laciniate, but not lobed; calyx-teeth dilated 

 below, often with 2 small lateral teeth : the tube 10-nerved or sometimes with intervening nerves 

 more or less developed below ; corolla 10-12 mm. long, reddish purple, the wings with dark tips, 

 the standard with pale or whitish tips. 



Open grassy fields and slopes, Transition and Upper Sonoran Zones; Vancouver Island to southern Cali- 

 fornia. Type locality: Columbia River. March-June. 



Trifolium tridentatum var. aciculare (Nutt.) McDermott, N. Amer. Trifol. 26. 1910. {Trifolium acicu- 

 tare Nutt. in Torr. & Gray, Fl. N. Amer. 1: 319. 1838.) Distinguished from the narrow-leaved form of the 

 typical species by the paler flowers, 20-25-nerved calyx-tube, and the usually entire teeth. This is the more 

 common form of this polymorphic species in the Sacramento-San Joaquin Valley and in southern California. 

 Type locality: Santa Barbara, California. 



48. Trifolium obtusiflorum Hook. Creek or Clammy Clover. Fig. 2703. 



Trifolium obtusiflorum Hook. Bot. Beechey 331. 1836-38. 



Trifolium tridentatum var. obtusiflorum S. Wats. Proc. Amer. Acad. 11: 130. 1876. 



Annual, soft-pubescent, clammy and acidulous, the stems 3-5 dm. high, stout and fistulous, 

 erect with ascending branches. Stipules spreading or reflexed, conspicuously setulose; leaflets 

 2-3 cm. long, linear-lanceolate to broadly oblanceolate, pectinately setulose; peduncles 3-8 cm. 

 long ; involucre small, deeply laciniate with subulate divisions ; heads 2-3 cm. broad ; calyx-tube 

 20-nerved, the teeth entire, dilated near the base; corolla 12 mm. long, white or pale rose with 

 a dark purple spot near the center. 



Moist places, especially creek bottoms, Transition and Upper Sonoran Zones; southwestern Oregon to south- 

 ern California. Type locality: near Monterey, California. April-July. 



49. Trifolium Gambellii Nutt. Gambell's Sour Clover. Fig. 2704. 



Trifolium Gambellii Nutt. Journ. Acad. Phila. II. 1: 151. 1848. 

 Trifolium fucatum var. Gambellii Jepson, Fl. W. Mid. Calif. 311. 1901. 



Stems branching from the base, procumbent, stout and fistulous, 5-8 dm. long. Stipules large 

 and scarious; leaflets entire or finely pectinate, rhombic, 15^0 mm. long; calyx-teeth much 

 elongated, bristle-like and one or more of them 2-3-cleft ; corolla white, tinged with yellow and 

 purple, 15-20 mm. long, the standard inflated in age. 



Moist places, Transition and Upper Sonoran Zones; locally distributed in Contra Costa, San Luis Obispo, 

 Ventura, and Los Angeles Counties, California. Type locality: Santa Catalina Island. April-June. 



