PIPER FLORA OF THE STATE OF WASHINGTON. 359 



Calyx teeth hairy, not plumose. 



Flowers red; stipules aristate 9. T. pratense. 



Flowers whitish; stipules not aristate. 



Flowers pedicelled; heads globose . 6. T. latifolium. 

 Flowers subsessile. 



Heads obovate; corollas not 

 inflated; leaflets soft; stip- 

 ules acuminate 7. T. longipes. 



Heads globose; corollas in- 

 flated; leaflets firm; stip- 

 ules obtusish 8. T. covillei. 



Annuals; roots fibrous. 

 Calyx teeth plumose. 



Heads ovate ; flowers dark purple 12. T. albojmrpureum 



Heads oblong; flowers pink 13. T. arvense. 



Calyx teeth not plumose. 



Corollas whitish, not becoming papery. 



Teeth of the calyx scarious-margined and 



ciliate 14. T. ciliolatum. 



Teeth of the calyx not scarious-margined 

 nor ciliate. 



Leaflets not notched at apex 15. 7". gracilentum. 



Leaflets notched at apex 16. T. Tiallii. 



Corollas yellow, becoming papery in age. 



Heads 20 to 40-flowered; standard distinctly 



striate 17. T. procumbens. 



Heads 3 to 15-flowered; standard faintly 



striate 18. T. dubium. 



Heads subtended by an involucre. 



Corolla becoming conspicuously inflated, yellowish 19. T. famdum. 



Corolla not becoming inflated. 



Involucre deeply cleft, the lobes laciniately toothed; 

 flowers dark purple. 



Perennial with creeping rootstocks 20. T . Jimbriatum. 



Annuals. 



Stems erect; calyx-lobes often 3-toothed; 



leaflets linear 21 . T. tridentatum. 



Stems decumbent ; calyx-lobes usually entire. 



Leaflets linear 22. T. oliganihum. 



Leaflets obovate or obcordate 23. T. variegatum- 



Involucre not deeply cleft, its lobes serrate or entire; 

 flowers white or pale pink , annuals. 



Glabrous; calyx teeth slender and branched 24. J . cyathiferum. 



Villous; calyx teeth scarious-margined. 



Involucre nearly inclosing the head 25. T. microdon. 



Involucre merely basal 26. T. microcephalvm. 



1. Trifolium macrocephalum (Pursh) Poir. Encyc. Suppl. 5: 336. 1817. 



Lupinasier macro cepalus Pursh, Fl. 2: 479. 1814. 



Tnjohum megacephalum Nutt. Gen. 2: 105. 1818. 



Type locality: "Headwaters of the Missouri." Collected by Lewis. The specimens 

 were really collected, however, at "Rock Fort Camp," the Dalles of the Columbia. 



Range; Eastern Washington, eastern Oregon, and Idaho. 



