442 



COMPOSITAE. 



[Vol. III. 



3. Thelesperma gracile (Torr.) A. Gra}'. 



Rayless Thelesperma. (Fig. 3953.) 



Bidens gracilis Torr. Ann. Lye. N. Y. 2: 215. 1827. 

 Thelesperma gracile A. Gra3', Kew Journ. Bot. i: 252. 



1849. 



Perennial from a deep root; stem rigid, branched, 



i-3 high, the branches nearly erect. Leaves 



rigid, erect or ascending, 2'-$' long, pinnately or 



bipinnately divided into linear segments, or the 



upper linear and entire; heads 6 // -ro // broad; rays 



usually none, sometimes present and 2 // ~3 // long; 



outer bracts of the involucre 4-6, oblong or ovate, 



mostly obtuse, very much shorter than the inner 



ones which are united to the middle or beyond; 



disk yellow or brownish; outer achenes slightly 



papillose; pappus-awns longer than the width of 



the summit of the achene. 



On dry plains, Nebraska and "Wyoming to Texas, 

 northern Mexico and Arizona. May-Aug. 



69. GALINSOGA R. & P. Prodr. Fl. Per. no. pi. 24.. 1794. 



Annual branching herbs, with opposite, mostly petioled, dentate or entire leaves, and 

 small peduncled heads of both tubular and radiate flowers, terminal and in the upper axils. 

 Involucre hemispheric or broadly campanulate, its bracts in 2 series, ovate, obtuse, mem- 

 branous, striate, nearly equal, or the outer shorter. Receptacle conic or elongated, its thin 

 chaff subtending the disk-flowers. Ray-flowers white, pistillate, fertile, the rays 4 or 5, short. 

 Disk-flowers yellow, perfect, the corolla 5-toothed. Anthers minutely sagittate at the 

 base. Style-branches tipped with acute appendages. Achenes angled, or the outer ones flat. 

 Pappus of the disk-flowers of several short laciniate or fimbriate scales, that of the ray-flow- 

 ers of several or few short slender bristles, or none. [Named in honor of M. M. Galinsoga, 

 superintendent of the Botanic Gardens at Madrid.] 



About 5 species, natives of tropical and warm temperate America. 



i. Galinsoga parvifldra Cav. Galinsoga. (Fig. 3954.) 



Galinsoga parviflora Cav. Icon. 3: 41. pi. 281. 1794. 



Slightly appressed-pubescent, i-3 high. Leaves 

 thin, ovate or deltoid-ovate, 3-nerved, i / -3 / long, acute 

 at the apex, mostly obtuse at the base, dentate, the 

 lower slender-petioled, the upper short-petioled or ses- 

 sile, and sometimes nearly or quite entire; heads usu- 

 ally numerous, 2 // ~3 // broad, slender-peduncled; bracts 

 of the involucre glabrous or nearly so, the outer 

 shorter; pappus of the disk-flowers 4-16, oblong to 

 spatulate, fimbriate obtusish scales, shorter than the 

 finely pubescent obpyramidal achene. 



In door-yards and waste places, eastern Massachusetts 

 to Oregon. North Carolina, Missouri and Mexico. Natu- 

 ralized from tropical America. Introduced into Europe 

 as a weed. June-Nov. 



Galinsoga parviflora hispida DC. Prodr. 5:677. 1836. 



Pubescence more abundant, especially above, spreading; 

 pappus of the disk-flowers attenuate, bristle-tipped. In 

 waste places, Rhode Island to Pennsylvania, North Caro- 

 lina and Wisconsin. 



70. ACTINOSPERMUM Ell. Bot. S. C. & Ga. 2: 448. 1824. 

 [Balduina Nutt. Gen. 2: 175. 1818. Not Baldwinia Raf. F. 1818.] 



Annual or perennial, simple or branched, erect herbs, with alternate entire narrow punctate 

 leaves, and large terminal heads of both tubular and radiate, yellow flowers, or those of the 

 disk purplish. Involucre hemispheric, its small bracts imbricated in several series, appressed, 

 or with spreading tips, the outer shorter. Receptacle convex, deeply honey-combed, chaffy, 

 the persistent chaff coriaceous or cartilaginous, laterally united, subtending the disk-flowers. 

 Rays large, neutral, toothed. Disk-flowers perfect, fertile, the corolla 5-toothed. Anthers 

 sagittate at the base. Style-branches with truncate subulate tips. Achenes turbinate, silky- 

 villous. Pappus of 7-12 scarious nearly equal scales. [Greek ray-seed.] 



Two known species, natives of the southeastern United States. 



