3o6 



COMPOSITAE. 



[Vol. III. 



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



Slcuder aqu.itic herbs, with linear entire verticillate leaves, ami solitary (rarel3' 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.) 



AElhulia untflora Walt. Fl. Car. 195. 1788. 

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



98. 1803. 

 Sclerolepis i-erticUlala Cass. Diet. 48: 155. 1S27. 

 Sclerolepis uniflora Porter, Mem. Terr. 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, yz"-\" 

 wide, or the submerged ones filiform; head about 

 5" broad; bracts of the involucre linear-oblong, 

 acutish, usually puberulent. 



In shallow ponds and streams, pine-barrens of New 

 Jersey to Florida. Jiily-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 i row. [Named for Mithridates Eupator, i. e., of a noble father.] 

 About 475 species, mostly of warm or tropical regions. Besides the following, some 3u otliers 

 occur in the southern and western parts of North America. 



4f Leaves alternate, pinnatifid into filiform segments, i. £", ccipilli/oli UIH. 

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

 Leaves thick, rugose, pubescent; inflorescence depressed. 2. E. niaculatum. 



Leaves thin, nearly glabrous; inflorescence pyramidal. 3. J', purpureum. 



-X- -^ "K- Leaves opposite (rarely in 3's), or the uppermost alternate, 

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



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

 2. Leaves all sessile, short-petioled or conuate-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. 

 Leaves oblong or lanceolate, coarsely toothed, H'-iJ^' wide. 

 Bracts of the involucre obtus^e. 



Leaves linear, crowded, usually entire, obtuse. 

 Leaves lanceolate, oval, or oblong, usually dentate. 

 Leaves linear-lanceolate, acute, dentate. 

 Leaves oblong to oval, sli,irply dentate, obtusish or acute. 

 Leaves lanceolate, sparingly dentate, long-acuminate. 



? i Leaves rounded, obtuse or truncate at the base. 

 Plant glabrous; leaves lanceolate, long-acuminate. 

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

 I.,eaves ovate-oblong, rounded at the base, usually obtuse. 

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



13. E. rolundi/olium. 

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



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

 Leaves connate-perfoliate; involucral bracts acute. 1.5. E. per/olialum. 



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



t t Inz'olucra! bracts in i or 2 series, alt equal or nearly so. 

 Receptacle flat; flowers white. 



Leaves thin, 2' -5' long, sharply dentate, acuminate. 17. E. ageratoides. 



5. E. leucolepis. 



6. E. album. 



7. E. hyssopi/olium. 



E. Torreyanum. 

 E. semiserratum. 

 E. allissimum. 



E. sessili/olium. 



E. verbenaefolium. 



