PIPER FLORA OF THE STATE OF WASHINGTON. 359 



Calyx teeth haiiy, not plumose. 



Flowers red ; stipules aristate 9. T. prafevse. 



Flowers whitish; stipules not aiistate. 



Flowers pedicelled; heads globo.se . (J. T. latifoJirnn. 

 Flowers subsessile. 



Heads obovate; corollas not 

 inflated: leaflets soft; stip- 

 ules acuminate 7.7'. hmgipex. 



Heads globose; corollas i.i- 

 flated; leaflets firm; .stip- 

 ules obtusish S. T. coriUei. 



Annuals; roots fibrous. 

 Calyx teeth plumose. 



Heads ovate; flowers dark purple 12. T. (ilhojmrpurfum- 



Heads oblong; flowers pink 13. 7'. arvense. 



Calyx teeth not plumose. 



Corollas whitish, not becoming paper\\ 



Teeth of the calyx scarious-margined aiul 



ciliate 14. 7'. cilid/d/inn. 



Teeth of the caly.x not scariou.s-margined 

 nor ciliate. 



Leaflets not notched at apex 15. T. gracilentum . 



Leaflets notched at apex 16. T. Tiallii. 



Corollas yellow, becoming papery in age. 



Heads 20 to 40-flowered; standard distinctly 



striate 17. T . jirocanibeus. 



Heads 3 to 15-fiowered; standard faintly 



striate IS. T. Juhium. 



Heads subtended by an involucre. 



Corolla becon^ng conspicuously inflated, yellowish 19. 7'. jiavuluju. 



Corolla not becoming inflated. 



Involucre deeply cleft, the lobes laciniately toothed; 

 flowers dark purple. 



Perennial with creeping rootstocks 20. T .Jimhriatutn. 



Annuals. 



Stems erect; caly.x-lobes often 3-toothed; 



leaflets linear 21 . 7\ Irldi ntatum. 



Stems decumbent ; calyx-lobes usually entire. 



Leaflets linear 22. T. oliganiluun. 



Leaflets obovate or obcordate 23. T. variegafuni 



Involucre not deeply cleft, its lobes serrate or entire; 

 flowers white or pale pink, annuals. 



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



Villous; calyx teeth scanous-margined. 



Involucre nearly inclosing the head 25. T. microdon. 



Involuci'e merely basal 2(). T. nncroci phahim. 



1. Trifolium macrocephalum (Pursh) Poir. Encyc. Suppl. 5: 330. 1.S17. 



Lu pinaster macrocepalus Pursh, Fl. 2: 479. 1S14. 



Jrijolium megacephalum Jvutt. Gen. 2: 105. 1818. 



Type locality: "Headwaters ot the Missouri." Collected b}' Lewis. The specimens 

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



Range; Eastern Washington, eastern Oregon, and Idaho. 



