184 COMPOSITE. (COMPOSITE FAMILY.) 



1. P. radiata, Michx. Leaves oblong, the upper ones clasping and toothed 

 at the base ; fruit mostly downy, ovoid, with a furrow between the parallel and 

 contiguous empty cells ; flowers white. River-banks, Florida, and northward. 

 February and March. Stem 6' - 12' high. 



ORDER 72. COMPOSITE. (COMPOSITE FAMILY.) 



Flowers clustered in a dense head upon a common receptacle, and sur- 

 rounded by an involucre. Calyx united with the ovary ; the limb (pap- 

 pus) either obsolete, or forming a cup-like or toothed border, or divided 

 into chaffy scales or bristles. Corolla superior, flat or funnel-shaped, 5- 

 (rarely 4-) lobed, valvate in the bud. Stamens alternate with the lobes 

 of the corolla, and inserted into its tube : anthers cohering in a cylinder 

 (syngenesious). Style single : stigmas 2. Fruit (achenium) dry and seed- 

 like. Seed solitary, erect, without albumen. Radicle inferior. Herbs 

 or shrubs. Leaves without stipules. Involucre composed of short or leafy 

 bracts (scales of the involucre), arranged in 1-many series. Receptacle 

 naked, or furnished with scales (chaffy). Heads with the flowers all tubu- 

 lar (discoid), or all strap-shaped, or the marginal ones strap-shaped or 

 ligulate (radiate). 



Artificial Synopsis of the Genera. 



SUBORDKR I. TUBULIFLOR^E. Corolla of the perfect flowers 

 tubular, equally 5- (rarely 3 - 4-) lobed. Ray-flowers, when present, 

 ligulate, either pistillate or neutral. 



1. Heads discoid. 



* Heads with the flowers all perfect. No. 



Pappus none. Leaves resinous-dotted. Flowers yellow. . . . FLAVERIA. 55 

 Pappus bristly or hairy. 

 Flowers yellow. 



Receptacle pointed BIGELOVIA. 21 



Receptacle flat NOB. 1 & 33 in SOLIDAGO. 20 



Receptacle convex . RUGELIA. 75 



Flowers white, blue, or purple. 

 Receptacle chaffy. 



Leaves opposite. Flowers white MELANTHERA. 40 



Leaves alternate. Flowers purple. . . . . . CARPHEPHORUS. 8 



Receptacle bristly. 



Leaves spiny CIRSIUM. 78 



Leaves not spiny, cordate LAPPA. 79 



Receptacle naked. 



Scales of the involucre in a single row CACALIA. 73 



Scales of the involucre in 2 or more rows. 



Pappus double, the outer row very short VEKNONIA. 1 



Pappus single. 

 Achenia ribbed or striate. 



Pappus plumose. Flowers cream -colored KUHNIA. 10 



Pappus scabrous. Leaves cordate BRICKELLIA. 11 



Pappus scabrous. Leaves not cordate. . LIATRIS. 9 



