Dewberry
Scientific name: Rubus caesius L.
Rubus caesius L. is the only species in the Section Caesii, and it is easily distinguished by its ternate leaves; thin, procumbent, glaucous stems with short (1-2mm), slender prickles; large flowers with broad, white petals; and glaucous fruits with few, large drupelets.
Diagnostic features of the Section Caesii
Stems low-arching to procumbent, (potentially) rooting at tips, with glaucous bloom, with moderate prickles but absent or few hairs or glands.
Leaflets 3, overlapping, the 2 basal sessile or nearly so.
Stipules lanceolate.
Flowers few, in corymbs, white, large (2-3cm across).
Fruits with large, few drupelets, black, with glaucous bloom.
Chromosome number: 2n=28, 35.
Habitat
Native; disturbed ground, grassland, scrub and sand-dunes, often on clayey or basic soils.
Distribution
Throughout Central & South British Isles but scattered and local in much of West and in Scotland.
This species is keyed out on Page 2266 in the Text Key.
Hybrids
- Rubus x pseudoidaeus (Weihe) Lej. (= Rubus idaeus x Rubus caesius) (Synonym: Rubus x idaeoides Ruthe) is very sparsely scattered in England, North Tipperary; it resembles Rubus caesius in habit and stem characters and Rubus idaeus in leaf characters. It is largely sterile, with undeveloped fruits or partially developed reddish-black ones. |
