This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
The habitat of this plant, first found in Ireland (now in two vice-counties there), is woods. The habit is higharching. The stem is stout, bluish-green, clothed with long, fine, shining hairs. The acicles are very unequally scattered, and stalked glands very rare or absent. The prickles are remarkably flattened and straight, long, slender. The leaves are greyish-green, the leaf-stalks long, with many unequal, partly gland-tipped organs. The panicle is cylindrical, the lowest branches moderately long and nearly erect. The rachis has very close, grey felt under the long hairs, with some of the long, slender prickles gland-tipped. The prickles are almost invariably straight and generally widely spreading. The sepals are bent back. The plant is remarkably grey. It resembles R. Questierii and R. micans or R. criniger, distinguished by the flattened slender prickles, inversely egg-shaped, terminal leaflet, more finely-pointed teeth, etc.
Rubus adenanthus, Boul & Gill. - The prickles on the stem of this species are strong, with numerous pricklets and stalked glands. The leaves are 3-5-lobed, with 3 lobes radiating from a common centre and 2 lateral, greyish-green, with ashy felt below, and compound deeply-cut teeth. The leaflets are ashy-felted and thinly hairy below, the terminal one broadly oval. The panicle is long, glandular, forming a more or less pyramidal corymb. The rachis and flower-stalk have crowded soft hair, which obscures the numerous unequal acicles and stalked glands. The sepals are long, widespreading, with sunken glands and long points ascending when the petals drop. The plant approaches R. micans in leaf characters and hairy stems, but is also like Radulan forms in other respects.
The habitat of this species is bushy places and hedges. The stem is not felted. The pricklets are usually numerous, with a stout base. The leaves are 5-lobed, with 3 lobes radiating from a common centre and 2 laterals, and 3-lobed. The leaflets are wavy at the edge, with an ashy felt and hair below. The panicle is cylindrical throughout, the branches rigid and strongly ascending, weakly armed in the ultra-axillary part. The small petals and style are dark-red. The stamens are not so long as the style. The sepals rise when the petals fall. The stout-based pricklets are characteristic, also the unarmed panicle rachis and rigid ascending branches, with small deep-red flowers.
The habitat of this plant is woods, thickets, and open commons. The stem is very bluntly angled and round, with many very small pricklets, acicles, and bristles, the armature on stem and panicle being variable. The leaflets have broad, shallow, even teeth, with close ashy-felt and rather few hairs below, the terminal leaflet roundish, inversely egg-shaped. The panicle is broadly cylindrical, with widespreading branches. The rachis and flower-stalk have an ashy felt, are densely softly hairy, and have many very slender more or less widespreading prickles. The stalked glands are crowded and sunken, with a few gland-tipped bristles. The plant approaches R. pulcherrimus, differing in armature, glands, etc, and shape of panicle.