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.