3. H. verticillàta, Thunb. Umbels few-flowered, proliferous, forming an interrupted spike; pedicels very short or none; fruit 1½–2´´ broad; dorsal and lateral ribs very prominent. (H. interrupta, Muhl.)—Mass. to Fla.
[*][*] Pericarp uniformly corky-thickened and ribs all filiform; leaves not peltate; peduncles much shorter than the petioles.
[+] Fruit small, without secondary ribs or reticulations; involucre small or none.
4. H. Americàna, L. Stems filiform, branching and creeping; leaves thin, round-reniform, crenate-lobed and the lobes crenate, shining; few-flowered umbels axillary and almost sessile; fruit less than 1´´ broad; intermediate ribs prominent; no oil-bearing layer; seed-section broadly oval.—Common. (Addendum) Propagating by filiform tuberiferous stolons.
5. H. ranunculoìdes, L. f. Usually floating; leaves thicker, round-reniform, 3–7-cleft, the lobes crenate; peduncles 1–3´ long, reflexed in fruit; capitate umbel 5–10-flowered; fruit 1–1½´´ broad; ribs rather obscure; seed-section oblong.—E. Penn. to Fla., thence westward.
[+][+] Fruit larger (2–2½´´ broad), with prominent secondary ribs and reticulations; the 2–4-flowered umbel subtended by two conspicuous bracts.
6. H. Asiática, L. Petioles and peduncles (1–2´ long) clustered on creeping stems or runners; leaves ovate-cordate, repand-toothed, thickish; seed-section narrowly oblong. (H. repanda, Pers.)—Md. to Fla. and Tex. (Widely distributed in the tropics and southern hemisphere.)
35. ERÝNGIUM, Tourn. Eryngo.
Calyx-teeth prominent, rigid and persistent. Styles slender. Fruit ovate or obovate, covered with little hyaline scales or tubercles, with no ribs, and usually 5 slender oil-tubes on each carpel.—Chiefly perennials, with coriaceous, toothed, cut, or prickly leaves, and blue or white bracted flowers closely sessile in dense heads. (A name used by Dioscorides, of uncertain origin.)
[*] Stout, with parallel-veined elongated linear thick leaves.