AGGREGATE. 571 



fruits, which are entirely without a pappus. There are only a few 

 flowers in the small capitula. Arnoseris (Swine's - succory ) y 

 Catananche, etc. 



B. The pappus is long and liairy (not branched), generally 

 fine and snowy- white. There are no scales on the receptacle. The 

 two genera first considered have beaked fruits. Taraxacum (Dan- 

 delion) (Fig. 606 a) ; the capitula are many -flowered, and borne 

 singly on the top of a leafless, hollow stalk. Lactuca (Lettuce) 

 has many small, few-flowered capitula borne in panicles. Crepis 

 (Hawksbeard). Hieracium (Hawk- weed) has many imbricate 

 involucral leaves, and a stiff, brittle, brownish pappus. Sonchus 

 (Sow-thistle) ; the capitula, when a little old, have a broad base,, 

 and are abstricted above in the form of a jug; involucral leaves- 

 imbricate ; the fruit is compressed, without a beak, ridged. The- 

 soft, white pappus falls off collectively. 



C. The pappus is feathery and branched; no scales on the recep- 

 tacle. Tragopogon (Goat's-beard) generally has 8 involucral leaves 

 in one whorl. The fruit has a long beak; the rays of the pappus 

 are interwoven in the form of an umbrella. Scorzonera has fruits 

 like the preceding, but almost without any beak; involucral leaves 

 many, imbricate. Leontodon (Hawkbit) has a slightly feathery 

 pappus, rays not interwoven ; beak absent. Picris. 



D. Long, chaff -like, deciduous scales on the receptacle ; pappus 

 feathery. Hypochceris (Cat's-ear). 



4. Eupatorieae, Hemp-agrimony Group. All the flowers 

 are most frequently '> corollas tubular and regular ; the in- 

 volucral leaves are not stiff and spiny; the receptacle is not 

 covered with stiff bristles. The stylar branches are long, club- 

 like, or gradually tapering. There is no swelling below the 

 stigma. 



Eupatorium (Hemp-agrimony) ; all the flowers are 5 Petasites 

 (Butterbur) ; ray-flowers ? , disc-flowers $ or 6* '> sometimes 

 dioecious. Capitula in racemes 1 or panicles. The leaves develop 

 after the flowering. Tussilago(T. farfara, Colt's-foot) has a soli- 

 tary capitulum borne on a scaly, scape-like stem; the ray- 

 flowers are $ with ligulate corollas, disc-flowers $ . The leaves 

 unfold after the flowering. Ageratum, Mikania, Vernonia. 



5. Asterese, Aster Group (or RADIATE, Ray-flowered). The 

 flowers are of two forms and different sexes; the ray-flowers 

 are ? (sometimes neuter), most frequently with irregular, falsely 

 ligulate, radiating corollas ; the disc-flowers are ? , regular, with: 



