1. Ribes diacanthum Pallas, Reise Russ. Reich. 3: 722, plate 1, fig. 2. 1776.
Plants dioecious, 0.5-2 m. Stems erect, stipitate-glandular, without nonglandular hairs; spines at nodes 2, 3-5 mm; prickles on internodes scattered. Leaves: petiole 1-2 cm, glabrous; blade ovate to obovate, 3-lobed, cleft barely 1/8 to midrib, 1.5-3.5 cm, base cuneate to rounded, surfaces glabrous abaxially, strigillose adaxially, lobes rounded, margins deeply serrate, apex obtuse. Inflorescences nodding, 10-15-flowered racemes, staminate 2-3 cm, pistillate 1-2 cm, axis glabrous, glandular, flowers evenly spaced. Pedicels jointed, 2-4 mm, pubescent and stipitate-glandular; bracts lanceolate to ligulate, 4-6 mm, glabrous. Flowers unisexual; hypanthium yellowish green, rotate, 1-1.5 mm, glabrous; sepals not overlapping, erect, greenish, ovate, 1.5-2 mm; petals widely separated, erect, greenish yellow, cuneate-orbiculate, not conspicuously revolute or inrolled, 0.5-1 mm; nectary disc not seen; stamens nearly as long as petals; filaments linear, 0.2-0.5 mm, glabrous; anthers cream, dumbbell-shaped, 0.2 mm, apex with depressed callus, (pollen absent in pistillate flowers); ovary (absent in staminate flowers) glabrous; styles connate almost to stigmas, 0.5 mm, glabrous. Berries palatable, red, globose to globose-ovoid, 5-10 mm, glabrous.
Flowering May-Jun. Disturbed areas; 400-500 m; introduced; Man.; n Asia.
Ribes diacanthum was first seen as apparently naturalized in 1947 in oak woods on bluffs near the Experimental Farm, Brandon, Manitoba; collections were made in 1956 and 1959 and deposited in DAO and the Experimental Farm herbarium (G. A. Stevenson 1965). Its current status in Manitoba is not known.