10. Rubus frondosus Bigelow (Yankee blackberry)
R. pratensis L.H. Bailey
Pl. 541 f–h; Map
2508
Canes to 200 cm
long and 70–130 cm tall, 3–7 mm in diameter. Prickles moderate, 0.5–1.2(–2.0)
per cm of cane, 2.5–5.0 mm long. Petioles with sparse to dense nonglandular
hairs, armed with fine, needlelike, downward-angled prickles to 3 mm long.
Stipules 10–18 mm long, linear to linear-lanceolate. Primocane leaflet margins
sharply toothed, the upper surface thinly hairy, the undersurface velvety
hairy. Central primocane leaflets (7–)8–14 cm long, (5–)6–11 cm wide, nearly
orbicular to ovate-elliptic, cordate to subcordate at the base, tapered to a
sharply pointed tip, the leaflet stalk about 1/6–3/10 as long as the leaflet
blade; middle leaflets rhombic to elliptic or elliptic-obovate, angled to
rounded at the base, tapered to a sharply pointed tip, stalked; basal leaflets
elliptic, angled at the base, tapered or short-tapered to a sharply pointed
tip, sessile. Inflorescences racemose, sometimes flaring toward the apex, but
typically compact, 3.0–17.5 cm long, 5–11 cm wide, with 1–11 flowers and 3–9
bracts, these leafy, about evenly divided between simple bracts and those with
3 leaflets; flower and inflorescence stalks with nonglandular hairs and rarely
with needlelike prickles. Sepals 6–10 mm long, 3–4 mm wide,
triangular-elliptic, tapered to a sharply pointed tip or abruptly tapered to a
short, slender point. Petals 8–14 mm long, obovate. Fruits 10–15 mm long, 10–16
mm wide, globose. May–June.
Scattered nearly
throughout the state (northeastern U.S. and adjacent Canada west to Kansas,
Iowa, and Minnesota). Bottomland forests, mesic to dry upland forests, banks of
streams, bases, ledges, and tops of bluffs, and upland prairies; also pastures,
old fields, old quarries, cemeteries, railroads, and roadsides.
Rubus
pratensis, a synonym of R.
frondosus (Widrlechner, 1998), was described based on a Missouri type (L.
H. Bailey, 1945) collected by B. F. Bush from a prairie in Cooper County. A
white-fruited form from Howell County was described as R. pensilvanicus
Poir. f. albinus E.J. Palmer & Steyerm..