1. H. arboréscens, L. (Wild Hydrangea.) Glabrous or nearly so, 1–8° high; leaves ovate, rarely heart-shaped, pointed, serrate, green both sides; cymes flat; flowers often all fertile, rarely all radiant.—Rocky banks, Penn. to Fla., west to Iowa and Mo.
2. H. radiàta, Walt. Leaves densely tomentose and paler or white beneath.—S. C. and Ga. to Tenn. and Mo.
11. DECUMÀRIA, L.
Flowers all fertile. Calyx-tube turbinate, 7–10-toothed, coherent with the ovary. Petals oblong, valvate in the bud. Stamens 20–30. Styles united into one, persistent. Stigma thick, 7–10-rayed. Capsule 10–15-ribbed, 7–10-celled, many-seeded, bursting at the sides, the thin partitions at length separating into numerous chaffy scales.—A smooth climbing shrub, with opposite ovate or oblong entire or serrate leaves, no stipules, and numerous fragrant white flowers in compound terminal cymes. (Name said to be derived from decem, ten, referring to the fact of its being often 10-merous.)
1. D. bárbara, L. Leaves shining, sometimes pubescent; capsule with the persistent style and stigma urn-shaped, pendulous.—Banks of streams; Dismal Swamp, Va., to Fla. and La.
12. PHILADÉLPHUS, L. Mock Orange or Syringa.
Calyx-tube top-shaped, coherent with the ovary; the limb 4–5-parted, spreading, persistent, valvate in the bud. Petals rounded or obovate, large, convolute in the bud. Stamens 20–40. Styles 3–5, united below or nearly to the top. Stigmas oblong or linear. Capsule 3–5-celled, splitting at length into as many pieces. Seeds very numerous, on thick placentæ projecting from the axis, pendulous, with a loose membranaceous coat prolonged at both ends.—Shrubs, with opposite often toothed leaves, no stipules, and solitary or cymose-clustered showy white flowers. (An ancient name, applied by Linnæus to this genus for no obvious reason.)
1. P. inodòrus, L. Glabrous; leaves ovate or ovate-oblong, pointed, entire or with some spreading teeth; flowers single or few at the ends of the diverging branches, pure white, scentless; calyx-lobes acute, scarcely longer than the tube.—Mountains of Va. to Ga. and Ala.
2. P. grandiflòrus, Willd. A tall shrub, with long and recurved branches; like the last, but somewhat pubescent, with larger flowers, and the calyx-lobes long and taper-pointed. (P. modorus, var. grandiflorus, Gray.)—Along streams, Va. to Fla. Often cultivated.
P. coronàrius, L., the common Mock Orange or Syringa of cultivation, from S. Eu., with cream-colored odorous flowers, has sometimes escaped.