Sp. Pl. ed. 2, 2: 1663. 1763.

Common names: Climbing-hydrangea wood-vamp
Etymology: Latin decumae, tenths, and -aria, possessing, alluding to sometimes 10-merous flowers
Treatment appears in FNA Volume 12. Treatment on page 489. Mentioned on page 463, 486.

Woody vines. Stems climbing, sometimes trailing and forming loose nonflowering mats. Bark exfoliating in grayish or reddish brown sheets, strips, or strings. Branches spreading laterally or declining; twigs glabrous or with simple trichomes. Leaves deciduous or semideciduous, opposite; petiole present; blade ovate, elliptic, obovate, oblanceolate, subround, or round, herbaceous, margins usually entire, rarely dentate or lobed, plane; venation pinnate. Inflorescences terminal, on shoots of the season, corymbs, (20–)50–100-flowered; peduncle present. Pedicels present. Flowers bisexual; perianth and androecium epigynous; hypanthium completely adnate to ovary, turbinate, strongly 7–12-ribbed in fruit; sepals persistent, 7–12, erect, triangular, glabrous; petals 7–12, valvate, spreading, white, lanceolate, elliptic, or oblong, base essentially sessile, surfaces glabrous; stamens 20–30; filaments distinct, dorsiventrally flattened, linear, tapering abruptly just proximal to apex, apex not 2-lobed; anthers suborbiculate to ovate; pistil 6–12-carpellate, ovary completely inferior, 6–12-locular; placentation axile proximally, parietal distally; style persistent, 1. Capsules turbinate, cartilaginous, dehiscence intercostal, lateral walls separating from ribs, eventually leaving cagelike remnants. Seeds 10–20 per locule, yellow, fusiform. x = 14.


se United States, Asia (China).


Species 2 (1 in the flora).

A molecular phylogenetic study of tribe Hydrangeeae (Y. De Smet et al. 2015) found Hydrangea to be polyphyletic. The authors promoted adoption of a broader, monophyletic concept of Hydrangea that includes all eight genera in the tribe, including Decumaria. Decumaria is treated here in its traditional sense.

Selected References


Lower Taxa