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.) 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.