448 CARDUACEAE. 



1. Parthenium Hysterophorus L. Sp. PI. 988. 1753. 



Animal, strigose-pubescent or somewhat villous, usually much branehed, 

 3-7 dm. high. Leaves ovate to oblong in outline, 1-2-pinnately parted into 

 linear or lanceolate, toothed or pinnatifid segments, thin, and flaccid; heads 

 numerous, 5-6 mm. broad; involucre saucer-shaped, its bracts concave, the 

 outer ones rhombic, the inner broader; ray-flowers few; rays reniform, white, 

 about 1 mm. wide; achenes obovate, about 1 mm. long. 



Waste places and pine-lands, Andros, New Providence, EleutlieTa to Watling's 

 Islattd, Long Island and Inagua ; — Bermuda ; United States to continental tropical 

 America; West Indies. Sakta Maeia. 



17. CEASSINA Scepin, Acido Veg. 42. 1758. 



[Zinnia L. Syst. ed. 10, 1221. 1759.] 



Annual or perennial herbs, some species shrubby, with opposite entire, or 

 sparingly serrate, mostly narrow and sessile leaves, and large or middle-sized 

 heads of both tubular and radiate flowers. Ray-flowers pistillate, yellow or 

 variegated, persistent on the achene. Disk-flowers perfect, fertile; corolla 

 cylindraeeous, its lobes villous. Involucre campanulate to nearly cylindrie, its 

 bracts obtuse, dry, firm, appressed, imbricated in 3 series or more, the outer 

 gradually shorter. Receptacle conic or cylindrie, chaffy, the chaff subtending 

 and enwrapping the disk-flowers. Style-branches elongated, not appendaged. 

 Achenes of the ray-flowers somewhat 3-angled, those of the disk flattened. 

 Pappus of few awns or teeth. [In honor of Paul Crassus, an Italian botanist 

 of the 16th century.] About 12 species, natives of western America. Type 

 species: Chrysogonum peruvianum L. 



1. Crassina multiflora (L.) Kiintze, Rev. Gen. 331. 1891. 



Zinnia nmltiflora L. Sp. PL ed. 2, 1269. 1763. 



Annual, erect, simple or branched, 1-6 dm. high, the branches nearly erect, 

 sparingly hispid. Leaves lanceolate, rough-hispid, thin, entire, 2-7 cm. long, 

 acute or acuminate at the apex, rounded at the nearly sessile base; peduncles 

 thickened upward, 1-6 cm. long; involucre campanulate, about 1.5 cm. high, its 

 bracts oblong, dark-margined above; rays obovate, 1-2 cm. long; receptacle- 

 scales obtuse, entire; disk-achenes 1-awned. 



Bahamas, collected by Swainson : — Cuba to Porto Eico and Guadeloupe ; Mexico 

 to Brazil and Peru. Zinnia. 



18. VEBBESINA L. Sp. PI. 901. 1763. 



Erect or diffuse, branching, pubescent or hirsute herbs, with opposite leaves, 

 and small peduncled terminal and axillary heads of tubular and radiate 

 whitish flowers. Involucre hemispheric or broadly campanulate, its bracts 

 imbricated in about 2 series, nearly equal, or the outer longer. Receptacle flat 

 or convex, chaffy, the chaff awn-like, subtending the achenes. Ray-flowers 

 pistillate, fertile. Disk-flowers perfect, mostly fertile, their corollas tubular, 

 4:-toothed or rarely 5-toothed. Anthers entire or minutely 2-toothed at the 

 base. Achenes thick, those of the rays 3-sided, those of the disk compressed. 

 Pappus none, or of a few short teeth. [.Name changed fromi Verbena.] 

 About 4 species, the following typical. 



