6. Rubus alumnus L.H. Bailey
R. pubifolius L.H. Bailey
Pl. 541 a, b;
Map 2504
Canes to 300 cm
long and 150–250 cm tall, 5–7 mm in diameter; primocanes occasionally with
scattered, gland-tipped hairs toward the tip but lacking nonglandular hairs.
Prickles moderate, 0.7–1.5 per cm of cane, 4–8 mm long. Petioles with sparse to
dense nonglandular hairs and sometimes gland-tipped hairs, armed with
broad-based, downward-curved prickles to 4 mm long. Stipules 7–21 mm long,
linear to linear-lanceolate. Primocane leaflet margins sharply toothed, the
upper surface thinly hairy, the undersurface velvety hairy. Central primocane
leaflets 8.5–15.5 cm long, 5–10 cm wide, elliptic to elliptic-oblong, cordate
to subcordate at the base, tapered to a sharply pointed tip, the leaflet stalk
about 1/4–1/3 as long as the leaflet blade; middle leaflets ovate to
ovate-elliptic, angled to rounded at the base, tapered to a sharply pointed
tip, stalked; basal leaflets ovate-elliptic, angled at the base, tapered to a
sharply pointed tip, nearly sessile. Inflorescences racemose, flaring broadly
toward the apex, 6–18 cm long, 6–10 cm wide, with 5–19 flowers, appearing leafy
with 2–7 bracts, about evenly divided between simple bracts and those with 3
leaflets; flower and inflorescence stalks with dense nonglandular hairs,
gland-tipped hairs, and scattered needlelike prickles. Sepals 6–10 mm long, 3–5
mm wide, triangular to narrowly triangular. Petals 10–22 mm long, broadly
obovate. Fruits 12–21 mm long, 9–18 mm wide, short cylindric. 2n=21, 28.
May–June.
Scattered,
mostly south of the Missouri River (northeastern U.S. west to Kansas, Iowa, and
Minnesota). Bottomland forests, mesic upland forests, banks of streams and
rivers, bottomland prairies, upland prairies, bases, ledges, and tops of
bluffs; also pastures, old fields, fallow fields, roadsides, and open, disturbed
areas.
Rubus alumnus was described by L. H. Bailey (1923)
from Missouri, with the type material collected by B. F. Bush in Jackson
County. Rubus pubifolius, a synonym of R. alumnus (Widrlechner,
1998), was also described from a Missouri type (L. H. Bailey 1945) collected by
J. H. Kellogg near Eagle Rock, in Barry County.