A tiny shrub (the smallest of all British ones), reaching rarely more than 2 in. above the ground (3 or 4 in. in gardens); stems glabrous, or slightly silky when young, creeping and taking root and often buried in the soil. Leaves usually only two or three at the end of the twig; round, broadly oval or obovate, 1⁄4 to 3⁄4 in. long, finely round-toothed, often notched at the apex and indented at the base, glossy green on both sides and usually glabrous, sometimes slightly silky when young, prominently net-veined; shortly but distinctly stalked. Catkins 1⁄4 to 3⁄4 in. long, appearing in April on short stalks; scales yellow or brown. Stamens two. Ovary glabrous or nearly so, conic.
Native of the mountains of Europe, including the northern British Isles, west through Iceland to N. America, where it occurs in Arctic regions and extends south on the Atlantic side to the mountains of New England and the Adirondacks. In spite of its name it is a true shrub, and makes an interesting tuft for a damp spot in the rock garden.
S. × cernua E. F. Linton S. herbacea × S. repens – A prostrate shrub, the young growths at first densely coated with appressed hairs, becoming glabrous and brown. Leaves oblong or ovate, to about 3⁄4 in. long, dark green and glossy, almost glabrous, above, prominently veined and usually coated with appressed hairs beneath, margins entire or finely toothed. Catkins with the leaves; scales sparsely hairy. Ovaries narrowly flask-shaped, varying from glabrous to densely downy, with a short style. This hybrid occurs occasionally in the mountains of Scotland.
S. × grahamii Borrer ex Baker – A hybrid of S. herbacea discovered by Prof. Graham (d. 1845) at Frouvyn in Sutherland, introduced to cultivation by him, and described in 1867 from specimens in the Borrer herbarium. It is a procumbent shrub of which only female forms are known. The leaves are elliptic-oblong to rounded, up to about 11⁄2 in., green and very sparsely hairy on both sides, with faintly toothed slightly wavy margins and a somewhat bent, acuminate tip. Stipules present, often persistent on strong shoots. Catkins 1⁄2 to 3⁄4 in. long; scales roundish, edged with red. Ovary thinly hairy, the long style and stigma reddish.
cv. ‘Moorei’. – Very like the type of S. × grahamii in all respects, save that the catkin-scales are narrow-oblong (S. moorei F. B. White; S. × Grahamii var. Moorei Lond. Cat. ed. 7).
‘Moorei’ was discovered by Dr David Moore on Muckish Mountain, Donegal, shortly before 1870, and introduced by him to the Glasnevin Botanic Garden, where it was propagated and further distributed. It is here assumed to be of the same parentage as S. × grahamii, but what species, crossed with S. herbacea, could have produced these plants is uncertain and controversial. Five species have been suggested by one authority or another. It is possible that S. × grahamii is a triple hybrid from S. herbacea, S. repens and S. aurita (R. D. Meikle in Stace, op. cit., p. 329).
S. × sadleri Syme S. herbacea × S. lanata – A dwarf shrub taking after S. herbacea in foliage, except that the leaves are larger and glaucous beneath. Catkins on leafy peduncles, after the leaves, showing the influence of S. lanata in their silky scales. It was originally discovered in 1874 at the head of Glen Callater, Aberdeenshire, by John Sadler, who was then assistant to J. H. Balfour, the Professor of Botany at Edinburgh, and later became curator of the Botanic Garden there. The same hybrid has been found elsewhere in Scotland, and in Scandinavia.
S. × simulatrix F. B. White S. herbacea × S. arbuscula – A low, spreading shrub with glossy, reddish brown branches, its leaves broadly ovate to roundish, soon glabrous, deep lustrous green above, paler and prominently veined beneath, to about 3⁄4 in. long. It has been found in Argyll and Perthshire and also occurs in Scandinavia. Only female plants are known in Britain; ovaries almost sessile, densely woolly. A similar hybrid between S. herbacea and S. foetida (S. arbuscula subsp. foetida) has been found in Switzerland and is cultivated in Germany in rock gardens.
S. polaris Wahlenb. – Very similar to S. herbacea in habit, but distinguished by its leaves being almost invariably entire, smaller, and not quite so rounded. The ovary is very hairy, not glabrous as in S. herbacea and the catkin-scales are dark brown or black. Native of Arctic regions. The true species may not be in cultivation.