This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Perennial or annual herbs, of various habit. Leaves small and rosulate or rarely large, with sheathing petioles. Calyx-tube short or long, free or adnate to the base of the ovary, 5-lobed. Petals 5, rarely unequal, sometimes fringed or glandular, perigynous or nearly hypogynous. Stamens 10, rarely 5, inserted with the petals. Capsule 2-celled, with 2 beaks, seeds numerous. About 160 species, chiefly from the mountains of the north temperate zone and arctic regions, a few extending to South America. The name is from the Latin saxum, a stone or rock, and frango, to break, from the reputed property of some species to break stone in the bladder, or the rocks they grow upon.
1. S. crassifolia (fig. 96). - About a foot high, with dark green glossy leaves and pink or purplish flowers, rarely exceeding the leaves, and appearing in March. This is a native of Siberia, and a common plant in gardens. S. ligulata, 8. ciliata: and S. cordifolia belong to this group. The first has strap-shaped glabrous fringed leaves and red or white flowers in May, and is a native of Nepal; the second, from the same country, has roundish hirsute and ciliate leaves and purplish flowers; and the third has deeply cordate leaves and purple flowers. It is a native of Siberia, not very distinct from the one figured. S. purpurascens, from Northern India, is the best of this section, but not quite hardy, and very rare.
Fig. 96. Saxifraga crassifolia. (1/4 nat. size.)
2. S. umbrosa. London Pride, None-so-pretty, St. Patrick's Cabbage. - This old favourite is so familiar as to render description almost superfluous. Leaves in dense tufts, obovate, crenate, narrowed at the base; petiole ciliated. Flower-stem leafless, slender; cymose flowers small, white or pink spotted with red or purple. There are several varieties of this and S. Geum, all of which are referred to one species by some writers. The extreme form of the latter has orbicular leaves, cordate or rounded at the base; but some of the varieties are intermediate between the two. Both are indigenous in Ireland and South-western Europe.
3. S. granulata. - This species belongs to another distinct section with radical palmately lobed leaves, suberect sepals, and white petals. It is a native, and the only lowland species with the exception of the inconspicuous S. tridactylUes, usually found on walls and buildings, extending to the South of England. It is distinguished by its granular bulbous roots and petiolate reniform-palmate glandular leaves. Flower-stems about a foot high. There is a double variety in cultivation. S. cernua is a similar but smaller plant, from mountainous districts of the north.
4. S. Hirculus. - The representative of a group with leafy stems and yellow petals and free sepals. In this species the radical leaves are rosulate, petiolate, lanceolate, and the cauline linear. A dwarf stoloniferous plant with few or solitary yellow flowers. Native of the northern parts of Britain, and widely distributed in Arctic and Alpine Europe, Asia, and North America.
5. S. oppositifolia. - The type of a section with opposite leaves, furnished with a pore at the tip. The present species grows in tufts. Stems slender, 2 to 3 inches high, thread-like, with a few small glabrous thick dark green leaves, and a comparatively large solitary terminal purple flower. A native species, and like the last of very wide distribution. This is a handsome little plant, flowering in Spring from April to June. There is a white and also a pink variety. S. bifldra, S. Kochii, and S. retusa are closely allied species.
6. S. hypnoldes. - Perennial, with many leafy flowerless shoots, alternate palmately lobed leaves, white flowers, and glandular articulate hairs. This species grows in dense tufts, the prostrate stems slender, often of considerable length. Leaves narrow, simple or 3-lobed; lobes acute. Flower-stems with few leaves. Common in the North of England and Scotland, and elsewhere in Europe. S. caespitosa, an indigenous species with obtusely lobed leaves and fewer barren shoots; S. muscoides, S. Androsacea, and a host of other Alpine species belong to this section; and S.ceratophylla, a very handsome allied species of dwarfer growth, with rigid sharply-cut leaves and relatively large white flowers, is a native of South-western Europe.
7. S. Aizoon. - A dwarf herb less than a foot high with rosulate oblong or ligulate leaves margined with sharp teeth and a grey incrustation, and pinkish white flowers. A native of the Alps of Europe. This and many other species with in-crusted leaves are more curious and interesting than ornamental. S. Cotyledon has tall branching flowering stems 2 to 3 feet high and white flowers; and 8. aretioldes is a diminutive plant about 2 inches high with glandular spathulate leaves and few yellow flowers. Both are found in the Pyrenees. S. Andrewsii and S. Guthrieana are hybrids, between this and the umbrosoe section.