194 COMPOSITE. (composite family.) 



sessile, 3-ncrved, sparingly serrate; corymbs dense; heads 15-20-flowcred ; 

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

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



* * Scales of the involucre purplish, scarious, obtuse, imbricated in sri>eral rows, the 



outer on s much shorter: leaves whorled : Jlowers purplish. 



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

 spotted or dotted ; leaves petiolcd, 3-6 in a whorl, varying from lanceolate to 

 ovate, coarsely serrate, roughish ; corymbs large, compound ; heads 5 - 10-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. ternifolium, E. maculatum, and E. verticillatum, 

 Ell. 



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

 shorter: heads 5 - 20flowered : leaves, achenia, $c. dotted with resinous glands: 

 flowers white. 



•*- Heads 5-foicered : leaves undivided, sessile or narrowed into a stalk-like base 

 (except No. 13.) 



3. E. hyssopifolitim, 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. lincarifolium, Walt.) — 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. CU.neifoli.um, 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 pubee 

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

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

 hoar] ; scales of the involucre lanceolate, acuminate, white and Bcarious ;it tin- 

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

 — Stem 2° high. Leaves l'-2' long. 



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



above; leaves alternate, opposite, Or whorled, lanceolate, acute, Btrongly 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 roan the 



mature a< licnia. — Margins of ponds and wet places, Florida to North Carolina, 



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

 ers smallest of all. 



7. E. scabridum, EIL1 Stem rtont, tomentose ; leaves opposite, ovate- 

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

 tose and somewhat glaucous beneath, 8-ribbed from mar the base] oorymbs 



