Narrative
Orig.- as a chance seedling in a wood in Dorsetshire, England. Parentage probably the native Rubus idaeus; introd. J.J. Kettle, Corfe Castle, Dorset; introd. into North America in 1923. Fruit: medium size, soft, dark, excellent flavor. Plant: moderately productive and vigorous. Resistant to the common strain of the North American aphid vector of the rasp-berry mosaic virus complex. Has been used extensively in North American breeding programs as a source of aphid resistance, conferred by gene Agi, and in both North American and European programs as a source of fruit quality, particularly flavor.Canes prbescent, non glaucous, slightly branched; prickles many, short, stiff, color at base and tip purple, base round, much raised, conspicuous; leaves ternate and quinate, strongly plicate, flat with some leaves reflex folded, terminal leaflet oval; apex medium in length, acute; serrations dull, shallow; basal leaflets stalked, slightly overlapping; length/ width ratio leass than 2.Outstanding characteristics: Pubescent canes, many purple prickles, with conspicuous bases; plicate leaves.Roberts, O.C. and A. S. Colby. 1957. Red and purple raspberries: their idendification from plant primocanes. University of Massachusetts Agri. Expt. Sta. Bul. 523. 27 pp.
Named for prime minister of England