11. Rosa setigera Michx. (prairie rose, climbing rose)

R. setigera var. tomentosa Torr. & A. Gray

Pl. 540 a, b; Map 2496

Stems 100–200(–600) cm long, sometimes tip-rooting, trailing or more commonly climbing on and through other vegetation, occasionally loosely twining, the tips often arched downward, usually relatively slender, green to light brown, glabrous or occasionally finely hairy, the prickles paired at the nodes and individual between the nodes, 5–9 mm long, 3–5 mm wide, broadened at the base, curved or occasionally some of them straight, stout, flattened, rarely unarmed. Leaves 8–12 cm long, the petiole and rachis usually finely hairy and with stalked glands, occasionally glabrous, sometimes also with small prickles. Stipules 12–15 mm long, the margins entire, but sparsely stalked-glandular, sometimes somewhat curved under, the auricle flared, 3–4 mm long. Leaflets 3 or 5, 30–50(–100) mm long, 15–40 mm wide, the terminal leaflet with a stalk 10–16 mm long, the blade ovate to elliptic-ovate, broadly angled or rounded at the base, angled or more commonly tapered to a sharply pointed tip, the margins simply or doubly toothed with 18–42 teeth per side, these relatively coarse, gland-tipped, the upper surface glossy, green to dark green, usually glabrous, the undersurface lighter green, glabrous or finely hairy (sometimes finely woolly), sometimes also glandular. Inflorescences on lateral branches from second year’s stems and axillary toward tips of current year’s growth, of solitary flowers or more commonly more or less flat-topped clusters or small panicles of 3–6(–15) flowers, the flower stalks 15–25 mm long, with stalked glands but usually lacking prickles, with 1 to several bracts, these slender, often shed early. Flowers not doubled, the hypanthium 4–6 mm long, with usually dense stalked glands, the mouth 0.5–1.0 mm in diameter. Sepals 10–18 mm long, 2–4 mm wide, all similar, the margins entire, the undersurface finely woolly and stalked-glandular, becoming reflexed and shed soon after flowering. Petals 18–25(–30) mm long, pink to reddish pink, rarely white. Pistils 20–25, the styles fused, glabrous, extending 5–6 mm beyond the mouth of the hypanthium, thus protruding noticeably. Hips 6–10 mm long, 6–9 mm wide, globose to subglobose, more or less fleshy, the surface red. glabrous or with scattered stalked glands. Achenes 17–22, 4–5 mm long. 2n=14. May–July.

Scattered nearly throughout the state (eastern U.S. [except some far-eastern states] west to Nebraska and Texas; introduced along the Atlantic Seaboard; Europe). Bottomland forests, mesic upland forests, banks of streams and rivers, margins of ponds, lakes, and sinkhole ponds, upland prairies, glades, bases, ledges, and tops of bluffs, edges of fens, and rarely swamps; also pastures, old fields, fencerows, ditches, old quarries, old mines, railroads, and roadsides.

Although the flowers of R. setigera appear perfect, they are functionally either staminate or pistillate (W. H. Lewis, 1958b). This results is some plants that do not set fruit and the necessity of having staminate and pistillate plants in proximity to ensure seed production.

Rosa setigera is sometimes cultivated and also has been used in horticultural crosses with European roses. Plants with prickly stems and hairy leaves have sometimes been called var. tomentosa Torr. & A. Gray, but this combination of characters does not circumscribe a discrete taxon (W. H. Lewis, 1958b). Rare plants with unarmed stems and hairy leaves have been called f. serena (E.J. Palmer & Steyerm.) Fernald, whereas those with unarmed stems and glabrous leaves have been called f. inermis E.J. Palmer & Steyerm. White flowered individuals are f. alba Steyerm. All of these variants have been reported from Missouri (Steyermark, 1963).