126 



LEGUMINOS.E. 



Trifolium. 



A genus of perhaps 200 or more species, in temperate and subtropical regions, chiefly of the 

 northern hemisphere. In North America it is most largely represented on the western side, only 

 five species being native in the Atlantic States, while 40 or more are found in the region west of 

 the Rocky Mountains, including a section with involucrate heads peculiar to the western parts of 

 North and South America. Most of the species of the Coast Ranges and interior valleys are 

 normally "winter annuals," the perennials belonging chiefly to the Sierra Nevada and cooler por- 

 tions of the State. Few of them are sufficiently abundant to yield any important amount of 

 forage, and none are equal in this respect to the commonly cultivated European species. 



* Heads not involucrate : leaflets 5 to 7 : flowers sessile : calyx-teeth filiform, 



Stout, somewhat villous : flowers spieate, very large. 1. 



Dwarf, densely villous : flowers umbellate, half an inch long : leaflets 



nearly entire. 2. 



Dwarf, alpine, somewhat pubescent : flowers spieate, very small : leaflets 



coarsely toothed. 3. 



* * Heads not involucrate : leaves 3-foliolate. 



Perennial or biennial : heads terminal : flowers sessile or nearly so. 

 More or less pubescent : calyx-teeth very narrow, much longer than 

 the tube, plumose or hairy. 

 Teeth filiform, curved, very plumose : usually pubescent : heads 



ovate. 

 Teeth straight, plumose : pubescent : heads ovate to oblong : leaf- 

 lets long and narrow. 

 Teeth straight, hairy : stem usually smooth : heads ovate. 

 Glabrous, stout : teeth subulate, twisted, twice longer than the tube : 



heads ovate to oblong. 

 Glabrous : teeth scarcely exceeding the tube. 



Slender : heads rather small : leaflets usually narrow and acuminate, 



coarsely veined and toothed. 

 Stouter : heads large : leaflets usually broader and obtuse. 

 Low and cespitose : heads very small : leaflets small, broad and ob- 

 tuse, finely reticulated and scarcely toothed. 

 Annual, pubescent : heads mostly terminal : flowers sessile : calyx-teeth 



long-filiform, very plumose. 

 Annuals, mostly glabrous : heads axillary : flowers shortly pedicellate : 

 calyx-teeth subulate, not plumose. 

 Glabrous : calyx-teeth lanceolate, rigid, the scarious margin rough- 



ciliate. 

 Glabrous or nearly so : calyx campanulate, the teeth equalling the 

 petals : heads rather dense. 

 Leaflets not notched. 

 Leaflets deeply notched or 2-cleft. 

 Subpubescent throughout : calyx narrow ; teeth shorter than the pet- 

 als : heads very loose. 

 Glabrous : flowers sessile : calyx short : corolla inflated. 



* * * Heads subtended by an involucre : annual. 



Corolla not becoming inflated : involucre not membranaceous, deeply 

 lobed, the lobes laciniately toothed. 

 Glabrous : heads many-flowered : calyx-teeth thin, long and narrow, 



gradually attenuate, entire or setosely cleft : ovules several. 

 Glabrous or glandular-puberulent : heads many-flowered : calyx-teeth 

 rigid, rather abruptly narrowed from a broad base into the 

 spinulose apex, entire or shortly toothed : ovules 2. 

 Glabrous, very slender : heads small : flowers little exceeding the 



calyx : teeth rigid, setosely acuminate, entire. 

 Often villous, small, very slender : flowers 1 to 4, very much longer 

 than the calyx : teeth thin, shortly acuminate. 

 Corolla not inflated : involucre membranaceous, at least at base, less 

 deeply lobed ; lobes entire or serrate. 

 Villous : lobes of involucre entire : calyx-teeth subulate, with broad 



scarious margin. 

 Villous : lobes 3-toothed : calyx-teeth triangular, acute ; margin nar- 

 row, serrulate. 

 Smooth : involucre very broad ; lobes serrate : calyx-teeth setosely 

 many-branched. 



plumose : perennial. 

 T. MEGACEPHAI.UM. 



T. Andersonii. 

 T. Lesiiioni. 



4. T. ERIOCEPHALUM. 



5. 



T. 



PLUJIOSUM. 



6. 



T. 



LOKGIPES. 



7. 



T. 



ALTISSIMUM. 



9. 



T. 



KlNGII. 



8. 



T. 



Beckwithii. 



10. 



T. 



BOLANDERI. 



11. 



T. 



MACEJEI. 



12. 



T. 



CILIATUM. 



13. 



T. 



GRACILENTUM. 



14. 



T. 



BIFIDUM. 



15. 



T. 



Breweri. 



25. 



T. 



DEPAUPERATUM. 



16. T. ISVOLTJCRATUM. 



17. T. TRIDEXTATUM. 



18. T. PATJCIFLORUM. 



19. T. MONANTHUM. 



20. T. MICROCEPHALUM. 



21. T. MICRODON. 



22. T. CYATHIFERTJM. 



