306 



COMPOSITAE. 



[Vol.. III. 



3. SCLEROLEPIS Cass. Bull. Soc. Philom. 1816: 198. 1816. 



Slender aquatic herbs, with linear entire verticillate leaves, and solitary (rarely 2-4) dis- 

 coid peduncled terminal heads of small purplish flowers. Involucre broadly campanulate or 

 hemispheric. Bracts imbricated in about 2 series. Receptacle conic, naked. Corolla regu- 

 lar, its tube short, its limb campanulate, 5-lobed. Anthers obtuse at the base. Style- 

 branches slender, obtuse. Pappus of 5 broad cartilaginous obtuse scales. Achenes 5-angled. 

 [Greek, hard scale, referring to the pappus.] 



A monotypic genus of eastern North America. 



i. Sclerolepis uniflora (Walt.) Porter. 

 Sclerolepis. (Fig. 3612.) 



AEthulia uniflora Walt. Fl. Car. 195. 1788. 

 Sparganophorus verticillatus Michx. Fl. Bor. Am. 2: 



98. 1803. 

 Sclerolepis verticillata Cass. Diet. 48: 155. 1827. 



Sclerolepis uniflora Porter, Mem. Torr. Club, 5: 311. 

 1894. 



Perennial; stem simple, decumbent at the base, 

 erect or ascending, glabrous or slightly pubescent, 

 i-2 long, leafy. Leaves sessile, verticillate in 

 4's-6's, linear, i-nerved, 4 // -i2 // long, ]/z"-\" 

 wide, or the submerged ones filiform; head about 

 5 7/ broad; bracts of the involucre linear-oblong, 

 acutish, usually puberulent. 



In shallow ponds and streams, pine-barrens of New 

 Jersey to Florida. July-Sept. 



4. EUPATORIUM L,. Sp. PI. 836. 1753. 

 Erect, mostly branching, perennial herbs, with opposite or verticillate, or sometimes 

 alternate, often punctate leaves, and in our species cymose-paniculate discoid heads of 

 white blue or purple flowers. Involucre oblong, ovoid, campanulate, or hemispheric, the 

 bracts imbricated in 2-several series. Receptacle flat, convex, or conic, naked. Corolla reg- 

 ular, its tube slender, its limb 5-lobed or 5-toothed. Anthers obtuse and entire at the base, 

 appendiculate at the apex. Style-branches elongated, flattened, or thickened above, stig- 

 matic at the base. Achenes 5-angled, truncate. Pappus of numerous capillary usually sca- 

 brous bristles arranged in 1 row. [Named for Mithridates Eupator, i. e., of a noble father.] 

 About 475 species, mostly of warm or tropical regions. Besides the following, some 30 others 

 occur in the southern and western parts of North America. 



H- Leaves alternate, pinnatifid into filiform segments. 1. E. capillifolium. 

 >f -x- Leaves petioled, verticillate in 3's-6's, or the upper opposite. 

 Leaves thick, rugose, pubescent; inflorescence depressed. 2. E. macula turn. 



Leaves thin, nearly glabrous; inflorescence pyramidal. 3. E. purpurenm. 



3fr -X- * Leaves opposite (rarely in 3's), or the uppermost alternate. 

 | Involucral bracts imbricated in 2 or more series, the outer shorter. 



1 . Leaves, at least the lower, slender-petioled. 4 

 2. Leaves all sessile, short-petioled or connate-perfoliate 

 a. Leaves not clasping nor connate-perfoliate. 

 # Leaves narrowed at the base. 

 Bracts of the involucre acute or cuspidate. 



Leaves linear-lanceolate, sparingly toothed, 2" -6" wide. 5. 



Leaves oblong or lanceolate, coarsely toothed, V^'-iVi' wide. 6. 



Bracts of the involucre obtuse. 



Leaves linear, crowded, usually entire, obtuse. 

 Leaves lanceolate, oval, or oblong, usually dentate. 

 Leaves linear-lanceolate, acute, dentate. 

 Leaves oblong to oval, sharply dentate, obtusish or acute. 

 Leaves lanceolate, sparingly dentate, long-acuminate. 



$ # Leaves rounded, obtuse or truncate at the base. 

 Plant glabrous; leaves lanceolate, long-acuminate. 11. E. 



Plants pubescent; leaves ovate or oblong, acute or obtuse. 



Leaves ovate-oblong, rounded at the base, usually obtuse. 12. E 



Leaves broadly ovate, crenate-dentate, mostly truncate at the base, obtusish. 



13- E 



E. seroli until. 



E. leucolepis. 

 E. album. 



7. E. hyssopifolintn. 



8. 



E. Torreyanum. 

 E. semiserratum. 



10. E. allissimum. 

 sessilifolium. 

 verbenaefoliu in . 

 rolnndifoliutn. 



Leaves ovate, dentate, acute. 14. E. pubescens. 



b. Leaves clasping or connate-perfoliate at the base. 

 Leaves connate-perfoliate; involucral bracts acute. 15. E. perfoliatum. 



Leaves merely clasping; involucral bracts obtuse. 16. E. resinosum. 



| t Involucral bracts in 1 or 2 series, all equal or nearly so. 

 Receptacle flat; flowers white. 



Leaves thin, 2'-$' long, sharply dentate, acuminate. 17. E. ageratoides. 



