274 COMPOSITE. Polymnia. 



wide; the wing of the petioles sinuate or pinnatifid. Heads large; the rays 

 an inch long, 10-15 in number, bright yellow ; the corolla of the disk dull 

 yellow. Acheuia large, striate. 



72. CHRYSOGONUM. Linn. ; Gcertn. fr. t. 174 ; DC.prodr. 5. p. 510. 



Heads many-flowered ; the ray-flowers about 5, pistillate; those of the 

 disk sterile. Involucre double, each of about 5 scales ; the exterior foliace- 

 ous, oblong, longer than the disk ; the interior chartaceous, roundish, con- 

 cave, embracing the fertile flower in its axil. Pi-eceptacle flat ; the linear 

 obtuse persistent chafT subtending the sterile flowers ; 2 or 3 usually adhe- 

 rent to the base of each inner involucral scale. Corolla of the disk cylindra- 

 ceous, 5-toothed. Style in the sterile flowers hispid above, undivided, or 

 sonietimes 2-cleft at the apex. Achenia of the ray obovate, obcompressed, 

 4-angled, somewhat convex on the back, enclosed in a scale of the involucre; 

 of the disk linear, abortive. Pappus small, coroniform, 2-3-toothed, and 

 divided to the base on the inner side, persistent. — A low tomentose-hirsute 

 perennial herb, nearly acaulescent when it begins to flower, producing several 

 stems, some of which are erect or ascending and floriferous, others prostrate 

 and stoloniferous. Leaves opposite, or clustered at the base, on long pe- 

 tioles, ovate or spatulate, crenate. Peduncles solitary, simple, naked, at 

 first short, at length elongated. Flowers bright yellow. 



C. Virginianum (Linn.)— Lam. ill. t. 713 ; Gfertn. fr. 2. p. 436, t. 174 

 (the pappus bad) ; Walt. ! Car. p. 217 ; Michx. ! fl. 2. p. 148 ; Pursh! 

 jl. 2. p. 579 ; Ell. ! sk. 2. p. 472. C. Virginianum & diotostephus, DC. ! I. c. 

 Diotostephus repens, Cass, in diet. sci. nat. 48. p. 453. Chrysanthemum 

 Virginianum, &c., Pluk. aim. t. 83, /. 4, S^- 1. 242, /. 3. _ 



Dry fertile soil, Maryland! to Florida! and Illinois! to Louisiana! 

 April-July. — We are confident that Cassini has founded two genera, and De 

 Candolle two species, upon one and the same plant. We have never seen a 

 pappus like Gaertner's figure, nor exactly as Cassini describes his Diotoste- 

 phus ; but it is almost always as stated by Michaux and Elliott, that is, 

 3-toothed ; and the middle tooth is often shorter, or irregularly crenate, and 

 probably sometimes nearly wanting, when it would accord with Cassini's 

 character. The plant, when it commences flowering, presents only a tuft of 

 radical leaves (with rather short petioles), and a single head on a short radi- 

 cal peduncle ; but the succeeding leaves are borne on elongated petioles, the 

 ascending stems at length 6-12 inches high, and the peduncles which are 

 always short before the heads expand, often attain the length of 2 or 3 inches- 

 When old, the leaves become rather glabrous. 



Div. 3. S 1 L P u I E 5; , DC. — Fertile and sterile flowers in the same heads ; 

 the former (3-20) ligulate, the ra3's deciduous; the latter numerous, central, 

 tubular. Fertile achenia obcompressed, sometimes winged, not corticate, 

 destitute of pappus, or mostly 2-toothed or 2-awned. Anthers united. 



73. SILPHIUM. Linn. ; Gcertn. fr. t. 171 ; Schkuhr, liandh. t. 262. 



Heads many-flowered ; the ray-flowers numerous, pistillate, the ligules in 

 a single series, but the flat ovaries in 2-3 rows ; those of the disk tubular. 



