Shrub to small tree to 10 m tall Stem: stout, smooth, with a sharp spine between end buds. Leaves: opposite to subopposite, stalked (0.6 - 2 cm), shiny dark green above, grayish green and sometimes lightly hairy beneath, 4 - 10 cm long, narrow oblong or elliptic to inversely egg-shaped with a wedge-shaped base and pointed tip, finely round-toothed, with two to four pairs of veins. Flowers: borne in dense clusters, yellowish green, with four petals and four stamens. Fruit: fleshy with two center seeds (drupe), black, spherical, each large seed with one narrow furrow.
Similar species: Rhamnus cathartica, Rhamnus davurica, Rhamnus japonica, and Rhamnus utilis have opposite to subopposite leaf arrangements and often have spines at the tips of the stems. Rhamnus cathartica grows to 7.5 m tall. Its leaves are up to 6 times longer than the leaf stalks, are elliptic to inversely egg-shaped or nearly circular, and have two to four lateral vein pairs. Rhamnus japonica grows to 3 m tall. Its leaves are more than six times longer than the leaf stalks, are inversely egg-shaped, and have three to five lateral vein pairs. Rhamnus utilis reaches 3 m tall. Its leaves are more than six times longer than the leaf stalk, are narrow elliptic and often widest at or beneath the middle, and have five to eight lateral vein pairs. Rhamnus davurica var. nipponica differs from the typical variety by having leaves that are 5 - 15 cm long with a light green lower surface.
Flowering: May to June
Habitat and ecology: Rhamnus davurica was introduced from Asia. It has become a weed at the Morton Arboretum in DuPage County, but is not as invasive as R. cathartica. It is very durable and weedy, growing in thicket borders and disturbed areas. Fire management seems to hep control this and other introduced buckthorns.
Occurence in the Chicago region: non-native
Notes: The Illinois Exotic Weed Act states that this species cannot be purchased, sold, distributed, or planted in Illinois without a permit issued by the Department of Natural Resources.
Etymology: Rhamnus is the ancient Greek name for buckthorn.
Author: The Morton Arboretum
Much like no. 4 [Rhamnus lanceolata Pursh], but the lvs, or many of them, opposite or subopposite, on petioles mostly 1-2 cm; pistillate fls 1-3 per axil. Native of ne. Asia, sparingly intr. into our range. (R. citrifolia)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
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