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 moist alpine and subalpine rocks, and sea cliffs. The plant has the rosette habit. The rootstock is thick, cylindrical, fleshy, branched, woody, stout, perennial, smelling of roses. The stems are annual, simple, fleshy. The buds are scale-like. The leaves are bluish-green, fleshy, inversely ovate, lance-shaped, alternate, oblong, smooth, above larger and crowded, acute, toothed at the apex. The flowers are yellow or purple, in compact, terminal, corymb like cymes, the parts in fours. The plant is dioecious. The sepals are narrow. The petals are linear, smaller, or wanting in female flowers. The scales are notched. There are 8 stamens. The plant is 6-18 in. high, flowering from May to August, and is a herbaceous perennial.
The habitat of this species is rocks and walls. The plant has the cushion habit. The plant is hairless or slightly glandular. The flowering stems are curved below, then erect; the barren stems are purplish, leafy, prostrate, rooting. The leaves are oblong, blunt, bright-green, alternate, nearly cylindric, narrow below, flat above, spreading. The flowers are white, with petals twice as long as the green sepals, oblong to lance-shaped, in a much-branched panicle, hairless. The plant is 3-5 in. high, flowering in July and August, and is a herbaceous perennial.
This plant is not uncommon on old walls and rocks. The plant has the cushion habit. The stems are all prostrate, then ascending, the plant loosely tufted, bluish-green, pink, glandular,downy, much-branched. The flowering-stems are weak, wavy, slender. The barren stems are short, with opposite, rounded or ovoid leaves in a rosette. The leaves are short, fleshy, thick, gibbous, bluish-green, equal below, reddish. The flowers are rose-white, in a small panicle or forked cyme, few, glandular, downy. The sepals, petals, and carpels may be in sixes. The sepals are ovate, blunt, as are the petals, the latter with pink streaks. The plant is 2-3 in. high, flowering in June and July, and is a herbaceous perennial.
The habitat of this Stone-crop is old walls in the E. of England, and the plant is very rare. The plant has the cushion habit. It is smooth, with an insipid taste. The stems form a loose tuft, the barren stems having crowded leaves in 6 rows, the flowering-stems looser, spreading or bent back. The leaves are cylindrical, linear, blunt, spreading, spurred below, the spurs acute, touching the stem. The flowers are yellow, in a corymb-like cyme, which is smooth and 3-branched. The flowers are more or less stalkless. The sepals are lance-shaped, acute, not gibbous; the petals are lance-shaped, acute. The plant is 3-6 in. high, flowering in July and August, and is a herbaceous perennial.
The habitat of this species is rocks and housetops, walls. The plant has the rosette habit. It is like the last, but larger. The leaves are in 6 series, cylindrical, the tips awl-like, crowded on the flowering shoots, bent back, green, convex both sides, spurred below, acute, spreading, numerous. The flowers are yellow in nearly flat-topped cymes, the outer branches bent back or spreading, stalked. The sepals are ovate, acute, not gibbous below, the petals lance-shaped, blunt. The anther-stalks and lateral edges of the carpels have glandular hairs. The plant is 6-12 in. high, flowering in June and July, and is a herbaceous perennial.
The habitat of this species is limestone rocks (hence rupestre). The plant has the rosette habit. The barren stems are short, with densely overlapping, appressed, bluish-green leaves. The plant is smooth. The stems are stout, loosely tufted, green or pink-tinged. The flowering stems have erect, scattered leaves. The leaves are linear, lance-shaped, flat, spurred below. The flowers are yellow, in flat-topped scorpioid, corymb-like cymes. The sepals are oblong, blunt, elliptic. The petals are lance-shaped, acute. The anthers are yellow, the stalks smooth, as are the ovaries. The plant is 6-10 in. high, flowering in June and July, and is a herbaceous perennial.
The habitat of this species is wet rocks, chiefly in the W. of England. The plant has the rosette habit. It is more slender than S. rupestre, of which it has been regarded as a subspecies. The barren stems are short, erect, with crowded leaves, which are lance-shaped, bright-, not bluish-green, spurred below, flattened, forming small rose-like tufts. The flowers are yellow, in compact, round-topped cymes. The sepals are ovate, the petals lance-shaped. The anther-stalks and ovaries are smooth. The plant is 6-10 in. high, flo wering in June and July, and is a herbaceous perennial.