COMPOSITAE. 985 



oblong -lanceolate or linear-lanceolate, acute or acuminate, denticulate or entire, 

 narrowed to a sessile base, or the lower petioled, 2-12 cm. long, 4-20 mm. wide ; 

 heads commonly numerous, 6-12 mm. broad, nearly sessile, or slender-peduncled ; 

 rays short, nearly white ; anthers brown ; achenes 4-toothed, or at length truncate. 

 Along streams, and in waste places, southern N. Y. to 111. and Neb., south to Fla., 

 Tex. and Mex. Naturalized from tropical Am. and widely distributed in warm 

 regions as a weed. July-Oct. 



58. TETRAGONOTHECA L. 



Erect perennial mostly branched herbs, with opposite sessile or connate-per- 

 foliate, broad dentate leaves, and large peduncled heads of tubular and radiate 

 yellow flowers. Involucre depressed-hemispheric, its principal bracts 4, large and 

 foliaceous, inserted in I series ; inner bracts 6-15, small, subtending the pistillate 

 ray-flowers. Receptacle conic, chaffy, the chaff concave, enwrapping the perfect 

 fertile disk-flowers, the corollas of which are slender and 5 -toothed. Anthers 

 entire or minutely 2-toothed at the base. Style-branches of the disk-flowers hispid, 

 tipped with elongated appendages. Achenes thick, 4-sided, truncate at the sum- 

 mit. Pappus none, or of several short scales. [Greek, 4-angled case, referring to 

 the involucre.] Three known species, of the southern U. S. and northern Mex. 



I. Tetragonotheca helianthoides L. TETRAGONOTHECA. (I. F. f. 3881.) 

 Viscidly pubescent; stem branched or simple, 3-7 dm. high. Leaves ovate, ovate- 

 oblong, or somewhat rhomboid, thin, coarsely and unequally dentate, acute at the 

 apex, narrowed at the base, sessile, or connate-perfoliate, 5-15 cm. long, 2-7 cm. 

 wide; heads usually few, 3-7.5 cm. broad; principal bracts broadly ovate, acute; 

 rays 6-10, strongly nerved, 2-3-toothed; achenes 4-sided, or nearly terete; pappus 

 none. In dry soil, Va. to Fla. and Ala. May-June. Sometimes flowering again 

 in the autumn. 



59. SPILANTHES Jacq. 



Annual branching herbs, or some species perennial, with opposite, usually 

 toothed leaves and rather small, long-peduncled discoid and radiate heads, termi- 

 nal, or in the upper axils, or rays wanting in some species. Involucre campanu- 

 late, its bracts in about 2 series, herbaceous, loosely appressed. Receptacle con- 

 vex or elongated, chaffy, its chaff embracing the disk-achenes and at length falling 

 away with them. Ray-flowers yellow, or white, pistillate. Disk-flowers yellow, 

 perfect, their corollas tubular with an expanded 4~5-cleft limb. Anthers truncate 

 at the base. Style -branches of the disk-flowers long, sometimes penicillate at the 

 summit. Ray-achenes 3-sided, or compressed, those of the disk- flowers compressed, 

 margined. Pappus of 1-3 awns, or more. [Greek, spot- or stain-flower, not signifi- 

 cant.] About 30 species, of warm and tropical regions. 



I. Spilanthes repens (Walt.) Michx. SPILANTHES. (I. F. f. 3882.) Peren- 

 nial, usually rooting at the lower nodes; stem slender, spreading or ascending, 2-6 

 dm. long. Leaves ovate to lanceolate, petioled, acute, acuminate, or the lower ob- 

 tuse, coarsely toothed, or nearly entire, 3-7 cm. long ; heads solitary at the ends of 

 the stem and branches, 12-20 mm. broad; bracts of the involucre oblong to oblong- 

 lanceolate; rays 8-12, yellow; receptacle narrowly conic; achenes oblong, most of 

 them roughened when mature and hispidulous. In moist or wet soil, Mo. to Tex., 

 east to S. Car. and Fla. June-Sept. 



60. RUDBECKIA L. 



Perennial or biennial (rarely annual), mostly rigid, usually rough or hispid 

 herbs, with alternate undivided lobed or pinnatifid leaves, and large long-peduncled 

 heads of tubular (mostly purple) and radiate (yellow) flowers. Involucre hemi- 

 spheric, its bracts imbricated in 2-4 series. Receptacle conic or convex, with chaffy 

 concave scales subtending or enveloping the disk-flowers. Ray-flowers neutral, 

 the rays entire or toothed. Disk-flowers perfect, fertile, their corollas 5-lobed, 

 Anthers entire or minutely 2-mucronate at the base. Style-branches tipped with 

 hirsute appendages. Achenes 4-angled, obtuse or truncate at the apex. Pappus 

 cororiiform, sometimes of 2-4 short teeth, or none. [In honor of Glaus Rudbeck, 

 1630-1702, Swedish anatomist and botanist.] About 27 species, of N. Am. and 



