18. Rubus flagellaris Willd. (northern dewberry)
Map 2516
Canes to
250(–450) cm long and 60 cm tall, 3–6 mm in diameter. Prickles moderate to
dense, (2)3–5 per cm of cane, (2–)3–4 mm long. Petioles with nonglandular
hairs, armed with downward-curved prickles to 3 mm long. Stipules 14–18 mm
long, linear to linear-lanceolate or narrowly elliptic. Primocane leaves mostly
with 5 leaflets, rarely with 3, margins coarsely, doubly, and sharply toothed,
the upper surface glabrous, the undersurface thinly hairy, often with small
prickles on the veins. Primocane central leaflets 6–9 cm long and 4–7 cm wide,
broadly ovate to ovate-elliptic, occasionally obovate, especially in
late-season growth, cordate to rounded at the base, shouldered to an abruptly
tapered, sharply pointed tip, the leaflet stalk about 1/4 as long as the
leaflet blade; middle leaflets elliptic-obovate, angled at the base,
short-tapered to a sharply pointed tip, short-stalked; basal leaflets elliptic,
angled at the base, angled to a sharply pointed tip, sessile. Inflorescences
9–22 cm long, with 1–6 flowers on long, ascending stalks, with 2–6 leafy
bracts, these mostly simple or mostly with 3 leaflets; flower and inflorescence
stalks nearly glabrous, with small downward-curved prickles. Sepals 6–8 mm
long, 3–4 mm wide, narrowly elliptic to triangular-elliptic, abruptly tapered
to a short, slender point. Petals 12–20 mm long, obovate. Fruits 10–20 mm long,
10–15 mm wide, globose to broadly oblong in outline. 2n=28, 35, 49.
May–June.
Scattered nearly
throughout the state, more abundantly south of the Missouri River (northeastern
U.S. west to Wisconsin and Oklahoma). Openings of mesic to dry upland forests,
upland prairies, banks of streams, tops of bluffs, and margins of sinkhole
ponds; also pastures, old fields, old mines, cemeteries, railroads, roadsides,
and open, disturbed areas.
Palmer and
Steyermark (1958) published the name R. flagellaris f. roseoplenus
E.J. Palmer & Steyermark based on a specimen collected by Palmer (59655)
in 1955 along a railroad in Barton County. This form was stated to differ from
the typical one in its doubled corollas with numerous pinkish-tinged petals.
However, the type specimen instead appears to represent an unusual plant of
sect. Arguti (although the specimen is incomplete and thus cannot be
determined to species with confidence).