A revision of the genus Pteronia (Compositae) . 



283 



Leaves ovate or ovate-lanceolate, broad at the base . 12. oppositifolia. 

 Leaves linear or linear-oblanceolate, narrowed to the 

 base. 

 Heads very acute just before expansion j leaves 



5-8 mm. long 13 - Incilioides. 



Heads obtuse before expansion ; leaves l*5-2*5 cm. 



long-. 

 Involucral bracts lanceolate, gradually acuminate 14. scabra. 



Involucral bracts broadly ovate, not acuminate . 15. centauroides. 



Heads corymbose at the ends of the shoots. 



Leaves with strongly undulate and crinkled margins, 



glandular-papillous .- -16. undulata. 



Leaves with straight margins, scabridulous . . .17. divaricata. 



Sect. III. Ciliatae— Leaves with usually conspicuously ciliate or pectinate 

 margins, otherwise glabrous and often viscid, rarely setose pilose on the 

 surfaces, mostly opposite. Heads solitary except in two or three species. 

 Achenes villous or glabrous. 

 Leaves acicular, subterete, narrow, tufted or alternate, 

 rarely opposite. 

 Involucral bracts shorter than the flowers, acute; 



flowers yellow .18. camphorata. 



Involucral bracts longer than the flowers, tailed- 



acuminate ; flowers apparently green . . .19. stricta. 

 Leaves never acicular and rarely tufted or alternate. 

 Leaves alternate. 



Leaves 2-4 cm. long ; heads 35 cm. long ; branches 



glabrous 20 - onobromoides. 



Leaves about 1 cm. long; heads 1*5 cm. long; branches 



woolly 2L villosa - 



Leaves opposite. 



Heads 1-flowered, densely glomerate at the ends of 



the shoots 35 - f^ciculata. 



Heads several-flowered, solitary or up to 3 together. 

 Leaves flat, 3-10 mm. broad. 



Involucral bracts broadly and transversely 

 saccate just below the apex. 

 Leaves setose-pilose on both surfaces . . 22. inflexa. 

 Leaves setose only on the margins . . .23. punctata. 

 Involucral bracts not saccate. 



Leaves setose-pilose on both surfaces ; in- 

 volucral bracts acute 24. utilis. 



Leaves setose only on the margins ; involucral 

 bracts rounded at the apex. 

 Branches glabrous ; leaves 1 -nerved, roughly 



ciliate 25 - ^enocarpa. 



Branches finely and densely puberulous ; 



leaves minutely scabrid-ciliolate . . 26. Mooreiana. 



