102 DICOTYLEDONOUS. 



the summit. Leaves digitately 5-parted ; segments incisely serrate, the mid- 

 dle lobe distinct to the base, lateral ones slighlly confluent at the base. Flow- 

 ers in somewhat capitate umbels, a part sterile, fertile ones nearly sessile ; 

 tube of the calyx echinate. Fruit oval. Seed flat on one side. 

 White. % May— Aug. Damp soils, common. 



Genus IV. ERYNGIUM. 



Flowers capitate. Calyx with a roughened tube, with 

 somewhat fohaceous lobes. Petals oblong, ovate, emarginate, 

 with a long infiexed point. Fi'uit obovate, crowned. Car- 

 pels semi-terete. Flowers bracteate, the lower large, the oth- 

 ers intermixed with the flowers, small, scale-like. 



1. E. Aquaticum. Stem glabrous, fistular, small. Leaves broadly linear, 

 remotely ciliate, with soft spines. P'loral leaves undivided, equal, ovate, acu- 

 minate, ilowzrs in heads. Petals chaffy. Button snake-root. 

 White. %■ June — July. Damp sous. • 



8. E. ViRGiNiANUM. Stem glabrous, fistular, branched, thickened at the 

 joints. Leaves long, lanceolate, incisely serrate, tapering at each extremity 

 with prominent rnidrib. Flowers in numerous heads. Involucre long, sub- 

 ulate, sessile, whitish on the under surface. 



White. %■ June. Damp soils. 4-6 feet. 



3. E. Aromaticum. Stem branchinar towards the summit, leafy, many 

 from each root. Leaves pinnately parted, crowded on the stem, bristly, with 

 a silvery cartilaginous margm Flowers in numerous heads on long pedun- 

 cles. Invohicre 5-leaved, leaves 3-cIeft. 



White. % August — Nov. Pine baiTcns Florida. 



4. E. ViRGATUM. Stem erect or decumbent, glabrous fistular. Leaves 

 epatulate, ovate, membranaceous, cauline ones on short petioles, toothed, or 

 sharply serrate. Invohicre 6-8 leaves, longer than the head ; chaff bicuspi- 

 date. * Flowers in heads in the angles of the branches near the summit. 



Pale blue. % July — Sept; In pine barrens. 1-3 feet. 



5. E. Baldwinii- Stem prostrate, often creeping, branching, filiform. 

 Leaves oval or ovate, petiolate, entire, or somewhat lobed, remotely toothed ; 

 upper ones usually sessile, 3-cleft, with narrow entire, lateral segments ; mid- 

 dle segment entire, or 2-3 toothed. Flowers in small heads on axillary pe- 

 duncles, with the involucre shorter than the heads. 



White. % June— July. Southern Ga. 



Genus V. HELOSCIADIUM. 



Calyx with an obsolete, or 5-toothed margin. Petals ovate, 

 entire. Carpels with 5 prominent ribs. Fruit compressed, 

 laterally ovate-oblong. Herbaceous plants, with compound 

 or many parted leaves. 



1. H. NoDiFLORUM. Stem procumbent, striate. Leaves pinnate ; segments 

 oblong, serrate ; upper ones sometimes ternate, with acute leaflets. Flowers 

 in unibels opposite the leaves, generally destitute of an involucre, sessile, or 

 on short peduncles ; petals expanding, acuminate; 



White. © April — June About Charleston in wet places. 2 feet. 



2. H Leptophyllum. Stem glabrous, slender, erect or diffuse. Leaves 

 ternate with linear segments ; cauline ones sessile or nearly so. UmbeU op- 

 posite the leaves, subsessile, involucre none. Fruit small glabrous 



White. June— -July. Louisiana. 6-24 in. 



