1. C. Americànum, Schwein. Stems slender, decumbent and forking; leaves principally opposite, roundish or somewhat heart-shaped, obscurely crenate-lobed; flowers distant, inconspicuous, nearly sessile (greenish tinged with yellow or purple).—Cold wet places, N. Scotia to N. Ga., west to Minn.
2. C. alternifòlium, L. Stems erect; leaves alternate, reniform-cordate, doubly crenate or somewhat lobed; flowers corymbose.—Decorah, Iowa, west to the Rocky Mts., and north through Brit. Amer. (Eu., Asia.)
9. PARNÁSSIA, Tourn. Grass of Parnassus.
Sepals 5, imbricated in the bud, slightly united at the base, and sometimes also with the base of the ovary, persistent. Petals 5, veiny, spreading, at length deciduous, imbricated in the bud; a cluster of somewhat united gland-tipped sterile filaments at the base of each. Proper stamens 5, alternate with the petals, persistent; anthers introrse or subextrorse. Ovary 1-celled, with 4 projecting parietal placentæ; stigmas 4, sessile, directly over the placentæ. Capsule 4-valved, the valves bearing the placentæ on their middle. Seeds very numerous, anatropous, with a thick wing-like seed-coat and little if any albumen. Embryo straight; cotyledons very short.—Perennial smooth herbs, with entire leaves, and solitary flowers on long scape-like stems, which usually bear a single sessile leaf. Petals white, with greenish or yellowish veins. (Named from Mount Parnassus; called Grass of Parnassus by Dioscorides.)
1. P. parviflòra, DC. Petals sessile, little longer than the calyx (3´´ long); sterile filaments about 7 in each set, slender; leaves ovate or oblong, tapering at base.—Sandy banks, Lab. to Mich., N. Minn., and westward.
2. P. palústris, L. Scapes 3–10´ high; leaves heart-shaped; flower nearly 1´ broad; petals sessile, rather longer than the calyx, few-veined; sterile filaments 9–15 in each set, slender.—Same range as the last. (Eu.)
3. P. Caroliniàna, Michx. Scapes 9´–2° high; flower 1–1½´ broad; petals sessile, more than twice as long as the calyx, many-veined; sterile filaments 3 in each set, stout, distinct almost to the base; leaves thickish, ovate or rounded, often heart shaped, usually but one low down on the scape and clasping.—Wet banks, N. Brunswick to Fla., west to Minn., Iowa, and La.
4. P. asarifòlia, Vent. Petals abruptly contracted into a claw at base; sterile filaments 3 in each set; leaves rounded, kidney-shaped; otherwise as in the foregoing.—High mountains of Va. and N. C.
10. HYDRÀNGEA, Gronov.
Calyx-tube hemispherical, 8–10 ribbed, coherent with the ovary, the limb 4–5-toothed. Petals ovate, valvate in the bud. Stamens 8–10, slender. Capsule 15-ribbed, crowned with the 2 diverging styles, 2-celled below, many-seeded, opening by a hole between the styles.—Shrubs, with opposite petioled leaves, no stipules, and numerous flowers in compound cymes. The marginal flowers are usually sterile and radiant, consisting merely of a showy membranaceous and colored flat and dilated calyx. (Name from ὕδωρ, water, and ἄγγος, a vase, from the shape of the capsule.)