PEA FAMILY 187 



1. Heads with a row of bracts at base, i. e., an in- 



volucre 



a. Plants tufted, mat-like, nearly stemless; bracts 



separate or nearly so 



(1) Leaflets entire, usually silky-hairy 



(a) Heads on a distinct, often long, stalk; 



bracts awl-shaped, often tiny T. dasyphyllum 



(b) Heads nearly sessile; bracts 2, of 3 leaf- 



lets each T. andinum 



(2) Leaflets toothed, smooth or nearly so; 



bracts oblong to obovate, blunt, en- 

 tire T. Pdrryi 



b. Plants with leafy stems, 4-20 in. high ; bracts . - 



united, the lobes long-pointed and usually 

 toothed; leaflets toothed, narrowly oblance- 

 olate to obovate T. involucrdtum 



2. Heads without an involucre 



a. Stems low, tufted; leaves basal 



(1) Flowers 1.2-3 cm. long; leaves smooth or 



nearly so 



(a) Flowers 1-3, 1.5-3 cm. long; leaflets 



mostly oblanceolate, toothed T.ndnum 



(b) Flowers mostly 10 or more, 12-15 mm. 



long 

 x. Leaflets toothed, ovate to nearly round, 



1-1.5 cm. long T. Hdydeni 



y. Leaflets entire, elliptic to oblong, 1.5-2 



cm. long T.Brandegei 



(2) Flowers 7-9 mm. long, several in a head; 



leaves hairy, ovate to oblong, toothed T. gymnocdrpum 



b. Stems leafy, scarcely tufted 



(1) Heads sessile; flowers red; leaves hairy T.pratense; red 



clover 



(2) Heads on a distinct, often long, stalk 



(a) Stems creeping; heads white, on stalks 



3-6 in. high ; leaves ovate to roundish, 

 toothed 7\ repens; white 



clover 



(b) Stems erect, .5-3 ft. high 



x. Cultivated or escaped from cultivation 

 into roadsides and fields 



