Prickly gooseberry occurs mostly in the eastern half of Missouri. Its spine-covered berries turn reddish purple when ripe. Despite the prickles, they are edible. It is a low, straggly shrub with rigid, spreading or trailing branches. It is generally armed with simple reddish or black slender spines along the stem.
Leaves are simple, alternate or clustered, 1–2 inches long or wide, overall shape is round to broadly egg-shaped, the base cut back sharply to slightly rounded, the margin with 3 or 5 lobes, lobes with teeth rounded to pointed; both surfaces hairy; undersurface more densely hairy and paler green than above; the leaf stalk slender, ½–1 inch long, hairy.
Trunk has the outer bark thin, papery, tan to brown, with spines (modified leaf stalks) and few to many recurved prickles (prickles that bend away and back; these are outgrowths of the bark). The inner layer of bark is reddish brown or purplish, smooth, with numerous light-colored pores. The wood is hard, fine-grained, white, with a dark pith.
Twigs are slender, at first tan to brown and hairy, later gray to almost black and smooth; spines slender, solitary or in groups of 2 or 3, straight, to ¾ inch long; young twigs often with numerous, slender reddish or black spines. In Missouri, this plant usually has dense bristles, or slender prickles, along the stems, but elsewhere, the degree of hairiness or spininess can vary.
Flowers April–June, single or in clusters of 2–4; the stalk bearing the flower clusters is ¼–1¼ inches long, lacking joints, hairs present, sometimes gland-tipped; petals 5, yellowish green; stamens 5, barely showing beyond the petals. The ovary (the swollen base of the flower, which will become the fruit) is spiny.
Fruits July–September, reddish purple, globe-shaped, ¼–½ inch in diameter, armed with long stiff prickles; seeds 10–20, dark brown.
Similar species: Not counting cultivated gooseberries, Missouri has 4 species in genus Ribes (pronounced RYE-beez) that may be encountered in natural habitats. The prickly gooseberry is the only one with prickles on the fruits. Here are the others:
- Missouri gooseberry (R. missouriense) is the most widespread gooseberry in the state. The fruits of this species are green, ripening to red or purple, and are smooth (they lack prickles). The drooping flowers have long stamens that extend far beyond the petals.
- Golden currant, or Missouri or buffalo currant (R. odoratum), is uncommon in the western part of the Ozarks, and it has also been introduced in Barton and Jefferson counties and in the city of St. Louis. It occurs on ledges and tops of bluffs and on roadsides and railroads. Stems lack bristles or spines; flowers are in clusters of 3–10, with the flower stalks jointed toward the tip. Its flowers, especially in the afternoon, have a strong fragrance, described as a combination of spicy cloves and sweet carnations. The fruits are smooth, yellow to greenish yellow, becoming black at maturity.
- American black currant, or eastern black currant (R. americanum) is uncommon and known only from Schuyler County, where it grows in a deep muck fen along the Chariton River, and (historically) from St. Louis city and county. Stems lack bristles or spines; the leaves are dotted with resinous glands on the undersurface; the flowers are in clusters of 6–15 flowers, with the flower stalks jointed toward the tip. The fruits are smooth, black, and not very tasty.