MACLOSKIE : COMPOSITE. 773 



b. Inner or all the achenes rostrate ; mostly herbs, with i -several series of processes or scales 

 at base of the rostrum. Heads many-flowered ; fruits conically broadening at the base. 

 Rostrum long, supporting the hairy, disciform pappus. Involucral-bracts I -seriate, with 

 a distinct calyculus. 8 1. Taraxacum, p. 900. 



b2. Achenes not rostrate, or without processes at base of the rostrum. 



c. Fruits compressed, io-2O-ribbed, truncate or at least not rostrate. Pappus-setae many 



seriate, of unequal hairs. Herbs or half-shrubs. 82. Sonchus, p. 901. 



c-2.. Fruits cylindrical or prismatic; not compressed; narrowing basewards. Pappus- 

 setae persisting. 



d. Fruits apically narrowing or even rostrate. Involucral scales 2-several-seriate, or 

 with a calyculus. Stem scapiform, i -headed. 



83. Agoseris (Troximon, Macrorhynchus), p. 902. 



d2. Fruits apically broad, truncate, with distinct ribs. Flowers mostly yellow (or 

 reddish, rarely white). Hairs of 2 kinds, glanduliferous and stellate. 



84. Hieracium, p. 903. 



i. VERNONIA Schreb. Ironweed. 



Heads having all the flowers tubular and alike, no ray. Involucre 

 shorter than the flowers, of many imbricated series. Receptacle naked. 

 Achenes cylindrical and ribbed. Pappus double, outer of minute scales, 

 inner of capillary bristles. Perennial herbs, with alternate leaves and 

 purple, corymbose flowers. 



Species 450, headquarters in Amer., United States to Argentina; also 

 Africa, Madagascar and Asia. 



V. NITIDULA Less. (Baccharis montevidensis Griseb.) 



Stem fruticose, terete, much branching, glabrous. Branches angulate. 

 Leaves sessile, coriaceous, oblong, i-rarely-penni-nerved, revolute, entire 

 or denticulate on margins, both surfaces glabrous and glandular. Cymes 

 subpanicled on ends of the branches. Heads pediceled, 7-8-flowered. 

 Involucre turbinate, its scales oblong, subacute, appressed. Achenes 

 hairy. 



(Brazil) ; N. Patagon., by Rio Negro, near Carmen. 



2. STEVIA Cav. 



Herbs or undershrubs, with all, or usually at least the lower, leaves 

 opposite, and with narrow, white or purplish heads, which are homoga- 

 mously 5-flowered. Invohicre cylindrical, of 5-6 narrow, subequal bracts. 

 Anthers apically appendaged, basally obtuse. Style-branches long, slen- 



