This section is from the book "Sub-Alpine Plants Or Flowers Of The Swiss Woods And Meadows", by H. Stuart Thompson. Also available from Amazon: Sub-Alpine Plants: Or, Flowers of the Swiss Woods and Meadows.
This is possibly only a large-flowered variety of the last, which assumes so many forms in the Alps. Flowers up to 26 mm. in diameter, solitary or in twos or threes. Leaves bright green on both sides and generally broader than those of H. vulgare. Dry Alpine pastures up to 7400 feet. June to August.
This large-flowered variety is particularly fine at Mont Cenis, in Savoy and the Ligurian Alps.
Messrs. Schinz and Keller in their Flore de la Suisse give two sub-species of H. vulgare, viz. H. barbalum Lam. and H. nummul-arium Miller. The leaves of the former are green and glabrescent, and those of the latter white-tomentose beneath.
In the Ligurian and Maritime Alps there are two pretty rose-coloured plants which Mr. Bicknell1 describes under H. vulgare:
Plant greyish by reason of the short hairs covering the stems, leaves, and pedicels. Flowers usually pink, rarely crimson or nearly white. Very common on dry banks in the littoral region.
Leaves light green, narrow, and shining, the upper ones as well as the pedicels glabrous, or nearly so. Flowers pink. Not common in the littoral region. Val Nervia, etc. It is very common about Pigna in the Ligurian Mountains.
Various other species grow in Spain and the Mediterranean district, among the foot-hills and lower mountains, several of which are worth cultivating.
The Rock Roses are of the easiest culture in almost any light, rather poor soil fully exposed to the sun; and they strike readily from cuttings. If cut back after flowering they tend to grow more compact. The hybrids are very numerous and many of them extremely beautiful, being in all shades of yellow, salmon-pink, rose, and crimson. Few plants are of greater value for the rockery, for in addition to their beauty they grow very quickly. The nomenclature, however, of this genus seems somewhat confused. The tendency to hybridise may partly account for this.
A genus closely allied to the last. The flowers are usually smaller and the habit shrubbier. The sepals are always 5, the 2 exterior being smaller; and the capsule is 3-celled.
A recumbent small undershrub, 3-10 inches high, with woody base and branching stems. Leaves linear, sub-obtuse, mucronate, green, not stipuled, rough-edged. Flowers solitary, yellow, 1-4 on the upper part of the branches. Pedicels thick, deflexed, shorter than the sepals. Valves of the capsules slightly open at maturity and containing 12 seeds.
1 Flora of Bordighiera and San Remo (1896).
Dry screes and limestone rocks. Common. May to July.
Central and Southern Europe as far north as the Baltic Isles; Mediterranean region, Western Asia. In Switzerland locally in Tessin, Grisons, the Rhone Valley, and other warm places. On Monte Torraggio in Liguria we have seen this plant at some 4000 feet.