8 PROCEEDINGS OF THE AMERICAN ACADEMY. 



or denticulate, narrowed below to a somewhat petiole-like base, decur- 

 rent upon the stem, sparingly pubescent above, tomentulose and gland- 

 ular-atomiferous beneath, at length somewhat glabrate : inflorescence 

 loose; heads 2 cm. high, about 20-flowered. — Nov. Veg. Desc. fasc. 1, 

 27 (1824), not Sesse & Mocino. — Michoacan : near Vallisoletum, 

 flowering in October and November, Lexarza. Gcerrero : vicinity of 

 Acapulco, Palmer, no. 144 (hb. Gr.). 



t- -1- Outer bracts of the invohicre elliptical or spatulate, two-thirds as long as the 

 inner; the latter glandless. 



4. T. pterocaulis, n. sp. Stems much branched ; ultimate branch- 

 lets subappressed-pubescent : leaves thin, ovate to ovate-lanceolate. 3 to 

 10 cm. long, 1.5 to 4 cm. broad, acute, mucronate, entire or denticulate, 

 sessile and decurrent upon the stem or narrowed to a short petiole-like 

 base, glabrous or nearly so above, sparingly pubescent beneath : inflores- 

 cence loose and comparatively few-headed ; heads 1.7 to 2 cm. high, 12- 

 14-flowered ; bracts of the proper (inner) involucre 8, linear-oblong, ob- 

 tusish or abruptly pointed at the tip, appressed-pnbescent. — Colima ; 

 Manzanillo, December, 1890, Palmer, no. 897 (hb. Gr.). 



4_ 4_ 4_ Outer bracts of the involucre 5, very large, ovate-lanceolate, copiously 



glandular. 



5. T. alata, D. Don. Stems erect, rigid, branching; branches terete, 

 foliaceous-winged : leaves oblong-ovate, 5 to 8 cm. long, 2.5 to 4 cm. 

 broad, acute, mucronate, denticulate, papillose-setose on both surfaces : 

 bracts of the outer involucre 2.5 to 4 cm. long, about 12 mm. broad, 

 longer than the proper involucre : heads 24-flowered. — Trans. Linn. 

 Soc. xvi. 192 ; DC. Prodr. vii. pt. 1, 68 ; Hemsl. Biol. Cent-Am. Bot. ii. 

 258. — Mexico : without locality, Sesse ^ Mocino. 



* * * Leaves eubsessile or narrowed to a shortly petioled base : stem wingless 

 (sometimes very narrowly and inconspicuously winged in T. riigulosa). 



1- Bracts of the outer involucre 5, large, foliaceous, ovate, usually exceeding the 



inner. 



6. T. longifolia, D. Don. Stems erect, leafy ; branches striate, sub- 

 appressed tawny-pubescent : leaves crowded, sessile or subsessile, lance- 

 olate, 3 to 8 cm. long, 1 to 2 cm. broad, acute or acuminate, entire to 

 shallowly dentate, sparingly pubescent above, more or less appressed-vil- 

 lous beneath, somewhat glabrate, usually conduplicate ; inflorescence 

 dense, many-headed, conspicuously glandular ; heads large, 2 to 2.5 cm. 

 high, 18-20-flowered. — Trans. Linn. Soc. xvi. 191 (1838) ; DC. Prodr. 



