OF ARTS AND SCIENCES. 129 



very small (so far as known) : calyx villous, two lines long, tlif lililbrni 

 plumose teeth exceeding the puri)lish petals : banner deeply hooded : 

 ovary smooth, 2-ovuled. — From Lassen's Peak, by J. G. Lenmion, 



++ *-* Pubescent: flowers small: ovary obovate, densely villous, 2-ovuleil, at 

 length exserted from tlie calyx. 



15. T. GYMNocARiH)x, Nutt. Leaflets ovate-oblong to oblanceolate : flowers 

 3 to 5 lines long, in rallier close heads. — T. subcaulescens, Gray, Bot. Ives's 

 Kep. 10. 



§ 8. Leaflets 3: heads not involucrate, axillary or rarely terminal : annuals. 



* Pubescent : heads mostly terminal : flowers sessile, not reflexed : calyx-teeth 

 long-filiform, very plumose : ovules 2. — Western. 



IG. T. Macr.«;i, H. & A. Flowers dark-purple, 3 lines long, in dense ovate 

 long-peduncled heads. — Var. DicnOTOMCM, Brewer. Taller and stouter, with 

 larger flowers : corolla more conspicuous, tipped with white. 7\ dichntommn, 

 H. & A. — From the Columbia River to vS. California. The typical Chilian 

 form appears to have nearly sessile heads and stouter calyx-teeth. 



« * Mostly glabrous : heads axillary, small : flowers shortly pedicellate, at 

 length reflexed : calyx-teeth subulate or short. 



•4- Calyx-teeth subulate: ovules 2. — Western species. (T. depauperatum might 

 be looked lor here.) 



17. T. ciLiATCM, Nutt. Glabrous : leaflets obtuse or retuse : calyx cani- 

 panulate ; teeth lanceolate, rigid, the scarious margin rough-ciliate. — PI. Gam- 

 bel. 152. T. ciliolaium, Benth. PI. Ilartw. 304. From the Columbia to S. 

 California. 



18. T. GRACiLENTUM, Torr. & Gray. Slender : peduncles rarely villous 

 with spreading hairs : leaflets retuse : heads rather dense : calyx canipanulate ; 

 teeth subulate, equalling the corolla. — T. denudatiim, Nutt. PI. Gambel. 152, 

 t. 24. From the Columbia to S. California. 



19. T. BiFiDUM, Gray. Leaflets narrow, deeply notched or cleft, the 

 sides sparingly toothed or entire : otherwise as the last. — Proc. Am. Acad. 

 6. 522. 



20. T. AMABiLE, HBK. Similar to T. fjrocilentum, but more decumbent, 

 pubescent : calyx-teeth linear-setaceous, somewhat villous. — Mexico and West- 

 ern South America. 



21. T. Breweri, Watson. See p. 132. 



22. T. Palmeri, Watson. See p. 132. 



•t- •<- Ovules 4 or more: low, decumbent: leaflets obcordate or obovate. — 

 Eastern species. 



23. T. Carolixianum, Michx. More or less pubescent : corolla 2 lines 

 long, scarcely exceeding the green subulate calyx-teeth. — Pennsylvania to 

 Florida and Texas. 



24. T. AMPHiANTucM, Torr. & Gray. Stoloniferous, very slender, nearly 

 glabrous : flowers few, 4 lines long : calyx-teeth slender, much shorter, equalling 



VOL. XI. (N. S. III.) 9 



