OKDER LXl. UMBEl.LIFERJS. 331 



ovate, acuminate. Flowers in heads. Petals cliaffy. — White. If. Juno 

 — July. Damp soils. Button Snake-root. 



2. E. Virginia'num, (Lam.) Stem glabrous, fistular, branched, thick- 

 ened at the joints. Leaves long, lanceolate, incisc-ly serrate, tapeniijj 

 at each extremity, with prominent midrib. Flowers in numerous heads. 

 Involucre long, subulate, sessile, whitish on the under surface. — White. 

 If. June. Damp soils. 4 — 6 feet. 



3. E. aromat'icum, (Bald.) Stem branching toward the summit, 

 leafy, many from each root. Leaves pinnatfly paJted, crowded on the 

 stem, bristly, with a silvery, cartilaginous margin. Flowers in numer- 

 ous heads, on long peduncles. Involucre 5-leaveci ,• leaves 3-cleft.— 

 White. %. Aug. — Nov. Pine-barrens. Florida. 



4. E. virga'tum, (Lam.) Stem erect or decumbent, glabrous, fistular. 

 Leaves s])atulate, ovate, membranaceous ; cauline ones on short peti- 

 oles, toothed or sharply serrate. Involucre 6 — 8 leaves, longer than 

 the head ; chaff bicuspidate. Flowers in heads, in the angles of the 

 branches near the summit. — Pale blue. If. July — Sept. In pine 

 barrens. 1 — 3 feet. 



5. E. Baldwin'ii, (Spreng.) Stein prostrate, often creeping, branch 

 ing, filiform. Leaves oval or ovate, petiolate, entire or somewhat lobed, 

 remotely toothed ; upjier ones usually sessile, 3-cleft, with narrow, en- 

 tire, lateral se>4ments ; middle segment entire or 2 — 3-toothed. Flow- 

 ers in small heads, on axillary peduncles, with the involucre shorter 

 than the heads. — White. If. June — July. Southern Geo. 



Tribe III.— AMMIN'EJS. 



Fruit compressed laterally, with primary ribs only. Umbels 

 compound. 



Genus V.— HELOSCIA'DIUM. Koch. 5—2. 

 (From the Greek helos, a marsh, and skiadion, an umbel.) 



Cali/x with an obsolete or 5-toothed margin. Petals ovate, 

 entire. Carpels with 5 prominent ribs. Fruit compressed lat- 

 erally, ovate-oblong. Herbaceous plants, with compound or 

 many-parted leaves. 



1. H. nodiflo'rum, (Koch.) {Sium nodijlorum of Ell) Stem pro- 

 cumbent, striate. Leaves pinnate ; segments i>blong, serrate ; upper 

 ones sometimes ternate, with acute leaflets. Flowers iu umbels, oppo- 

 site tlie leaves, generally destitute of an involucre, sessile or on short 

 peduncles. Pfia/.s expaJiding, acuminate. — White. 0. April — June. 

 About Charleston. In wet places. 2 feet. 



2. H. leptopiiyl'lum, (D. C.) Stein glabrous, slender, erect or diffuse. 

 Leaves ternate, with linear segments ; cauline ones sessile or nearly so. 

 Umbels opposite the leaves, subsessile. Involucre none. Fruit small, 

 glabrous. — White. June — July. Lou. 6 — 24 inches. 



Genus VI— DISCOPLEU'RA. D. C. 5—2. Ammi, Ell. 

 (From the Greek diskos, a disk, and pleura, a rib.) 



Cahjx with subulate teeth, persistent. Petals ovate, entire, 



