454 CARDUACEAE. 



shorter than the inner; rays^ when present, white, 1-2 cm. long, '2-3-lobed; 

 achenes fusiform, unequal^ the inner longer than the involucre; pappus of 2-4 

 yellow, downwardly barbed awns. 



Waste and cultivated ground, New Providence, Great Bahama, Andros, South 

 Cat Cay, Eleuthera, Cat Island, Fortune Island and East Caicos : — southern United 

 States ; West Indies and Bermuda ; continental tropical America. White Beggab- 

 TiCKS. Shephebd's-needlb. 



27. TRIDAX L. Sp. PI. 900. 1753. 



Perennial herbs, with opposite, dentate or incised leaves and long-pe- 

 duncled heads of tubular and radiate flowers, the disk-flowers perfect and 

 fertile, the ray-flowers pistillate, the rays often 3-lobed. Involucre ovoid to 

 hemispheric, its nearly equal bracts in few series, or the outer smaller than 

 the inner. Receptacle flat or convex, the chaff subtending the disk-flowers. 

 Anthers auricled at the base or sagittate. Style-branches of the disk-flowers 

 subulate-appendaged. Achenes silky- villous. Pappus of many aristate 

 plumose scales. [Greek^ referring to the o-lobed rays.] About a dozen 

 species, natives of tropical America, the following typical. 



1. Tridax procumbens L. Sp. PI. 900. 1753. 



Hirsute, branched from the base, the branches spreading or ascending, 

 slender, 2-5 dm. long. Leaves ovate to ovate-lanceolate, short-petioled, 2-6 

 cm. long, incised-dentate, acute or acuminate at the apex, mostly cuneate at 

 the base; peduncles solitary, terminal, 1-3 dm. long; involucre subcampanu- 

 late, about 6 mm. high, its bracts hispid, the inner elliptic, the outer lanceo- 

 late; rays nearly white; achenes about 2 mm. long. 



Waste places. Lignum Vitae Cay, New Providence, Eleuthera, Cat Island and 

 Fortune Island : — Florida ; Cuba ; Grenada ; continental tropical America. Recorded 

 by Hitchcock as Amellus aspera (Jacq.) Kuntze. Twdax. 



28. FLAVERIA Juss.; J. F. Gmel. Syst. 2: 1269. 1791. 



Glabrous or minutely puberulent^ light green, annual or perennial herbs, 

 with opposite sessile leaves, and small, 1-several-flowered, usually sessile, oblong, 

 densely cymose-capitate heads of tubular, or both tubular and radiate, yellow 

 or yellowish flowers. Involucre of 2-5 narrow, nearly equal, appressed bracts, 

 sometimes with 1 or 2 additional small exterior ones. Receptacle small, naked. 

 Ray-flower commonly one, pistillate, fertile, sometimes wanting. Disk-flowers 

 1-15, perfect, fertile, their corollas 5-toothed. Anthers entire at the base. 

 Style-branches of the disk-flowers truncate. Achenes oblong or linear-oblong, 

 8-10-ribbed. Pappus none. [Latin, flavus, yellow, from its dyeing properties.] 

 Type species: Flaveria chilensis J. F. Gmel. 



1. Flaveria linearis Lag. Gen. et Sp. Nov. 33. 1S16. 



Perennial, glabrous or nearly so, somewhat woody, usually branched, 

 erect or decumbent, 3-9 dm. long. Leaves linear, entire, 3-7 cm. long, 1-6 mm. 

 wide; heads commonly numerous, in terminal corymbose cymes, short-pe- 

 duncled; involucre narrow, about 4 mm. high, its principal bracts about 5, 

 lanceolate or oblong, acute; ray-flower usually only one, its ligule 3-4 mm. 

 long. 



Coastal coppices and scrub-lands, Joulter's Cays, Andros. New Providence, 

 Water Cav on Cay Sal bank : — Florida ; Cuba ; Alacran Shoals ; Yucatan. The Cay 

 Sal bank plant is of a broad-leaved race. Nakeow-leaved Flaveria. 



