33. ERIGÈNIA, Nutt. Harbinger-of-Spring.
Calyx-teeth obsolete. Petals obovate or spatulate, flat, entire. Fruit didymous, nearly orbicular and laterally flattened, the carpels incurved at top and bottom, nearly kidney-form, with 5 very slender ribs, and several (1–3) small oil-tubes in the intervals; inner face of the seed hollowed into a broad deep cavity.—A small glabrous vernal plant, producing from a deep round tuber a simple stem, bearing one or two 2–3-ternately divided leaves, and a somewhat imperfect and leafy-bracted compound umbel. Flowers few, white. (Name from ἠριγένεια, born in the spring.)
1. E. bulbòsa, Nutt. Stem 3–9´ high; leaf-segments linear-oblong; fruit 1´´ long, 1½´´ broad.—W. New York to Md. and Tenn., and west to Wisc., S. E. Minn., and Kan.
34. HYDROCÓTYLE, Tourn. Water Pennywort.
Calyx-teeth obsolete. Fruit strongly flattened laterally, orbicular or shield-shaped; the carpels 5-ribbed, two of the ribs enlarged and often forming a thickened margin; oil-tubes none, but usually a conspicuous oil-bearing layer beneath the epidermis.—Low, mostly smooth, marsh or aquatic perennials, with slender creeping stems, and round shield-shaped or kidney-form leaves, with scale-like stipules. Flowers small, white, in simple umbels or clusters, which are either single or proliferous (one above another), appearing all summer. (Name from ὕδωρ, water, and κοτύλη, a flat cup, the peltate leaves of several species being somewhat cup-shaped.)
[*] Pericarp thin except at the broad corky dorsal and lateral ribs; leaves round-peltate, crenate; peduncles as long as the petioles, from creeping rootstocks.
[+] Fruit notched at base and apex; intermediate ribs corky.
1. H. umbellàta, L. Umbels many-flowered, simple (sometimes proliferous); pedicels 2–6´´ long; fruit about 1½´´ broad, strongly notched, the dorsal ribs prominent but obtuse.—Mass. to Minn., south to the Gulf.
2. H. Cánbyi, Coult. & Rose. Umbels 3–9-flowered, generally proliferous; pedicels very short, but distinct; fruit about 2 lines broad; carpels broader and more flattened than in the preceding, sharper margined, the dorsal and lateral ribs much more prominent; seed-section much narrower. (H. umbellata, var.? ambigua, Gray, Manual).—N. J. to Md.
[+][+] Fruit not notched; intermediate ribs not corky.