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 stem of this plant is stiffly hairy, woolly-felted, glandular above. The radical leaves are dull-green, spotted, bluish-green below, the outer oval to oblong, blunt, toothed, narrow below, the inner egg-shaped to lance-shaped, narrow both ends, toothed, the teeth curving forwards and below, purple-spotted, stiffly hairy, woolly-felted, the margins fringed with hairs. The 1-4 stem-leaves are smaller upwards, the lower stalked, egg-shaped to lance-shaped, linear, toothed. The panicle is branching, with close, erect to spreading, arching branches, longer than the acladium. The flower-stalks are rather short, woolly - felted, glandular, hairy. The heads are dark-green, egg-shaped at the base. The phyllaries are linear, lance-shaped, extending outwards, the innermost awl-like, woolly-felted, glandular, hairy. The ligules are yellow, hairless at the tip. The style is yellow, soon discolouring.
Hieracium duriceps, F. J. Hanb. - The habitat of this plant is rocky cliffs and burns, limestone rocks. The stem is wiry, reddish-purple, stiffly hairy below, nearly smooth above. The radical leaves are small, the primary oval to oblong, the later inversely lance-shaped, acute, wedge-shaped below, with 3-6 acute teeth, dull-green, with purple spots, stiffly hairy below. The 1-3 stemleaves are narrow, lance-shaped, toothed, the upper linear, entire. The panicle has 2-3 erect, straight branches, the upper spreading, arching, longer than the short-stalked acladium, the stalks are slender, rigid, woolly-felted, hairy. The 2-6 heads are small, hard, inversely conical. The phyllaries are deep-green, awl-like, narrow above, blunt, woolly-felted, stiffly hairy, glandular. The ligules are golden, tipped with stiff hairs. The styles are livid. The plant is 15-20 ft., flowering from June to August, and is a herbaceous perennial.
The habitat of this plant is slate quarries, etc. The stem is slender, rigid, stiffly hairy below, glandular above. The outer radical leaves soon fade, and are oval to oblong, elliptic, entire or toothed, the inner lance-shaped, toothed, acute, narrowed below, stiffly hairy on the nerves below, fringed with hairs at the border. The 2-8 stem-leaves are narrow, lance-shaped, entire, the lower like the inner basal leaves. The panicle has the lower branches erect to spreading, the upper close, ascending, longer than the acladium. The stalks are slender, woolly-felted, glandular, hairy. The heads are slender, long, egg-shaped, rounded. The phyllaries are narrow, linear to lance-shaped, acute, the tips of the inner curved, woolly-felted at the border, senescent, glandular, hairy. The ligules are hairless. The styles are yellow.
Hieracium orcadense, W. R. Linton. - The habitat of this plant is cliffs. The stem is finely furrowed, reddish, stiffly hairy, woolly-felted below, hairy above. The radical outer leaves are oblong to inversely egg-shaped, broad, rounded, narrowed below, the inner lance-shaped, acute, toothed each side, wedge-shaped below, hairy both sides and on the border. The 2-4 stem-leaves are stalked, like the inner basal leaves, with acute teeth. The panicle is close and compact, with close branches, the lower nearly erect, the upper curved, longer than the acladium. The 4-10 heads are dark, cylindric, blunt-based. The stalks are woolly-felted, hairy, glandular. The phyllaries are dark-olive, broad, blunt, with a pale border, senescent, woolly-felted below, hairy, glandular. The ligules are golden, with hairless tips. The styles are pale-olive, then dark-livid. The plant is 1-2 ft. high, flowering in July and August, and is a herbaceous perennial.