194 coMPOsiTiE. (composite family.) 



sessile, 3-nerved, sparingly seiTate ; corymbs dense ; heads 1 5 - 20-flowered ; 

 scales of the involucre very obtuse, strongly striate. — Near Natchez, Mississippi, 

 and South Florida. July -November. — Flowers blue. 



* * Scctles of the involucre purplish^ scanous^ obtuse, imbricated in several rows, the 



outer ones much shorter : leaves whorled : Jiowers purplish. 



2. E. purpureum, L. Smooth or pubescent; stem simple, tall, often 

 spotted or dotted ; leaves petioled, 3-6 in a vphorl, varying from lanceolate to 

 ovate, coarsely serrate, ronghish ; corymbs large, compound ; heads 5 - lO-flow- 

 ered. — Swamps, rarely in dry woods, Florida to Mississippi, and northward. 

 Aug. -Sept. — Stem 3° -10° high, solid or hollow, even or grooved. A vari- 

 able species, including E. ternifoliura, E. maculatum, and E. verticillatum, 

 Ell. 



* * * Scales of the involucre {green or white) imbricated in 2-3 rows, the outer ones 

 shorter : heads 5 - 20-Jiowered : leaves, achenia, Sj-c. dotted with resinous glands ; 

 Jiowers white. 



-- Heads 5-Jlowered: leaves undivided, sessile or narrowed into a stalk-like base 

 (except No. 13.) 



3. E. hyssopifolium, L. Pubescent ; leaves opposite, the upper ones 

 alternate, lanceolate or ovate-lanceolate, coarsely serrate or toothed, 3-ribbed at 

 the base ; scales of the involucre lanceolate, obtuse, mucronate, shorter than the 

 flowers. (E. linearifolium. Wall.) — Varies with the leaves narrow-linear and 

 entire, the lower ones 4 in a whorl, and numerous smaller ones in the axils. — 

 Low ground, Florida to Mississippi, and northward. Sept. — Stem 2'*- 3° 

 high. Leaves rigid, sometimes all alternate. 



4. E. euneifolium, Willd. Pubescent; leaves short, obovate-oblong, 

 sparingly serrate near the summit, or entire, 3-ribbed, mostly very obtuse ; scales 

 of the involucre obtuse, shorter than the flowers. (E. glaucescens. Ell.) — Rich 

 shaded soil, Florida to South Carolina. Sept. — Stem 2° - 3° high. Leaves 1' 

 long, pale and somewhat glaucous on both sides. 



5. E. leucolepis, Torr. & Gray. Stem simple, virgate, minutely pubes' 

 cent and roughened ; leaves somewhat remote, lanceolate or linear-lanceolate, 

 acute, serrate, very rough on both sides, obscurely 3-ribbed ; corymbs ample, 

 hoary ; scales of the involucre lanceolate, acuminate, white and scarioas at the . 

 apex, as long as the flowers. — Flat pine barrens, Florida and northward. Sept. 

 — Stem 2° high. Leaves 1 ' - 2' long. 



6. E. parviflorum, Ell. Tomentose ; stem slender, simple or branched 

 above ; leaves alternate, opposite, or whorled, lanceolate, acute, strongly serrate, 

 3-ribbed near the base, tapering into a petiole ; corymbs large ; scales of the in- 

 volucre lanceolate, obtuse, shorter than the flowers, scarcely longer than the 

 mature achenia. — Margins of ponds and wet places, Florida to North Carolina, 

 and westward. Sept. — Stem 2° high. Leaves 2' long, strongly veined. Flow- 

 ers smallest of all. 



7. E. sca/bridum, Ell. ? Stem stout, tomentose ; leaves opposite, ovate- 

 lanceolate, acute at both ends, thickly and unequally serrate, rough above, tomen- 

 tose and somewhat glaucous beneath, 3-ribbed from near the base; corymbs 



