Oriental bittersweet (Invasive Plants of Pittsburgh)

Oriental bittersweet

Celastrus orbiculatus

Summary ⁷

Oriental Staff Vine (Celastrus orbiculatus) is a woody vine native to East Asia of the Celastraceae family. It is also commonly called Oriental Bittersweet, Japanese Bittersweet or Asiatic Bittersweet. Oriental staff vine was introduced into North America in 1879, and is considered to be an invasive species in eastern North America. It closely resembles the native North American species, Celastrus scandens, with which it will readily hybridize.

Description ⁸

Deciduous twining shrubs; branchlets glabrous, gray- brown or brown, with sparse and inconspicuous lenticels; axillary buds small, ovate to elliptic, 1-3 mm. Petiole slender, 1-2 cm; leaf blade generally broadly ovate, suborbicular, or rectangular-elliptic, 5-13 × 3-9 cm, glabrous or abaxially sparsely pubescent on veins, base broadly cuneate to obtuse-orbicular, margin serrate, apex broadly rounded, muriculate, or shortly acuminate; secondary veins 3-5 pairs. Cymes axillary, sometimes terminal, 1-3 cm, 1-7-flowered; pedicels jointed below middle or nearly to base. Male flowers: sepals obtuse-triangular; petals obovate-elliptic to rectangular, 3-4 × 2-2.5 mm; disk shallowly cupuliform, lobe shallow, apex rounded-obtuse; stamens 2-3 mm. Female flowers: corolla relatively shorter than that of male flower; disk slightly thick, carnose; staminodes very short; ovary approximately globose; styles ca. 1.5 mm; stigma deeply 3-lobed, lobe apex shallowly 2-lobed. Capsule approximately globose, 8-13 mm wide, yellow, 3-valved. Seeds elliptic, slightly flat, 4-5 × 2.5-3 mm, reddish brown; aril orange-red. Fl. May-Jun, fr. Jul-Oct.