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 is woods and dry places, rarely on walls, basaltic hills and limestone rocks, mountain slopes. The stem is smooth, or stiffly hairy, woolly-felted, glandular above. The radical leaves are thin, membranous, elliptic, lance-shaped, blunt or heart-shaped, arrow-shaped below, toothed, the teeth horizontal or bent back, stiffly hairy on the veins below. The solitary stem-leaf is broad, linear, acute, toothed. The panicle is corymbose, the lower branches erect or spreading, ascending. The upper branches are close, in an umbel, ascending, exceeding the acladium. The heads are cylindric, egg-shaped, medium or small. The stalks are glandular, woolly-felted, stiffly hairy. The phyllaries extend forwards, and are narrow, woolly-felted, stiffly hairy, glandular. The ligules are yellow or golden, smooth above, fringed with hairs. The styles are livid or yellow. The margins of the receptacle pits are slightly raised, with cut teeth, or shortly toothed.
The habitat of this species is rocky streams, margins of alpine streamlets. The stem is erect, reddish, woolly-felted. The primary radical leaves are round, the outer egg-shaped, oblong, elliptic, rounded, pointed at the tip, blunt, narrow below, toothed, the inner egg-shaped, lance-shaped, acute, toothed, the leaf-base running down the stem, the innermost narrow, lance-shaped, acute, stiffly hairy below. There is no stem-leaf or a small one, linear or lance-shaped. The panicle is in a sort of umbel, with 1-2 distant lower, erect, branches, 1-2-headed, the upper branches or stalks aggregate (hence aggregatum), spreading, ascending or erect, exceeding the acladium. The stalks are long, erect, woolly-felted. The 4-10 heads are dark-green, rounded, egg-shaped. The phyllaries meet together in bud, and are awl-like, lance-shaped, blunt, the inner linear, lance-shaped, acute, with a pale border, woolly-felted, hairy, glandular. The styles are yellow. The ligules are smooth. The plant is 12-20 in. in height, flowering in July and August, and is a herbaceous perennial.
Hieracium oxyodus, W. R. Linton. - The stem of this plant is slender, furrowed, purplish, stiffly hairy and woolly-felted. The radical leaves are dull-green, reddish-purple, the outer small, oval to oblong, toothed, the inner oblong to lance-shaped, acute, wedge-shaped below or narrower, toothed below, stiffly' hairy below and on the margins. The stem-leaves are 1-2, the lower narrow, lance-shaped, toothed below, narrowed to the winged leaf-stalk, the upper bract-like. The panicle is rather narrowed into a sort of umbel, with erect lower branch, the branches erect, aggregate, in a sort of umbel. The 4-7 or 20 heads are dark, cylindric, egg-shaped, running down the stalk. The stalks are woolly-felted, glandular, hairy. The phyllaries meet together in bud, the outer hairy, triangular, lance-shaped, the inner linear, the innermost narrow, with broad, pale borders, hairy, glandular. The ligules are stiffly hairy at the tip. The styles are dull.