Saxifraga Saxifraga, L. Saxifraga Saxifraga, L.

91. S. rivularis L. View in CoL , Sp. Pl. 404 (1753).

Like 90 but usually smaller in all its parts and with underground, shortly creeping stolons arising from the bulbils; basal leaves usually 10-15 mm wide, 3- to 5-lobed; lobes of cauline leaves ovate-lanceolate, obtuse; petals 3-5 mm; ovary immersed for of its height. 2« = 52. Arctic and subarctic Europe, southwards to S. Norway and C. Scotland. Br Fa Fe Is N o Rs (N) Sb Su. S. hyperborea R.Br. in Parry, Jour. Voy. N. W.Pass. (Suppl. App.) 274 (1824), recorded from Svalbard (also from Greenland and arctic America), has usually been included under 91, but possibly deserves specific status. It differs in the reddish colour of the whole plant (including petals), the smaller petals and the absence of stolons. It has 2« = 26.

92. S. cernua L. View in CoL , Sp. Pl. 403 (1753).

Basal leaves 15-25 mm wide, reniform, 5- to 7-lobed, subglabrous, with long petiole; cauline leaves numerous, similar , but with progressively shorter petioles and fewer, deeper and more acute lobes; all with reddish bulbils in their axils. Stem up to 30 cm but often much less, usually simple, with a solitary, terminal flower (very rarely several flowers, one on each branch), which is, however, often abortive. Petals in well-developed flowers 8-12 mm, white, glabrous; ovary superior or very slightly immersed in receptacle. Seeds unknown, reproduction being entirely by bulbils. 2« = 50, 64. Arctic and subarctic Europe, southwards to c. 57° N. in Scotland and Ural; Alps; Carpathians. Au Br Cz Fe He Is It N o Po Rm Rs (N, C) SbSu. S. x opdalensis Blytt, Christ. Vidensk.-Sels. Forh. 1892: 52 (1892) ( S. cernua x rivularis ) is frequent in one district of Norway, near Opdal, apparently dispersed by bulbils from a single original cross. It is stouter than either of the parent species; it resembles S. cernua in having bulbils in the axils of the cauline leaves, but they are greenish, the petals are smaller (6 mm), and the ovary more deeply immersed in the receptacle. (A) Evergreen perennials, perennating by epigeal stolons or sterile, leafy shoots; leaves opposite, sessile, undivided, with marginal hydathodes, often lime-encrusted; ovary semi-inferior.

93. S. oppositifolia L. View in CoL , Sp. Pl. 402 (1753).

Stems procumbent or ascending, forming a loose mat or a more or less compact cushion. Leaves 2-6 mm, opposite (the upper ones rarely alternate), suborbicular to obovate-lanceolate, of a dull, often bluish green, thick, keeled below, plane or somewhat recurved at the tip, ciliate at least towards the base; hydathodes 1-5. Flowering stems very short, leafy, glandular-pubescent, 1-flowered. Sepals ciliate. Petals 5-15 x 2-7 mm, pale pink to deep purple; anthers bluish. 2« = 26. Arctic and subarctic Europe and on most o f the mountain-ranges southwards to the Sierra Nevada, C. Italy and Bulgaria. Al Au Br Bu Cz Fa Fe G a Ge H b He Hs Is It Ju No Po Rm Rs (N) Sb Su. Extremely variable in habit, size and colour of flower, form, size and ciliation of leaf, and number of hydathodes. This variation shows little geographical consistency, and in view o f the wide range of the species the elevation to subspecific rank of local populations of characteristic facies is scarcely justified. Among the variants that are often treated as subspecies (here cited for convenience by their binomials) are: S. rudolphiana Hornsch. ex Koch, Syn. FI. Germ. 269 (1835). Very compact; small in all its parts; leaves c. 2 mm, densely imbricate. E. (? and C.) Alps. S. blepharophylla Kerner ex Hayek , Österr. Bot. Zeitschr. 52: 329 (1902). Leaves very obtuse, with long cilia in apical half. Austrian Alps. S. murithiana Tiss. , Bull. Trav. Soc. Murith. 1: 27 (1868). Cilia of calyx gland-tipped; leaves with 1 hydathode. S. W. Europe and Alps. S. latina (N. Terrace.) Hayek, Denkschr. Akad. Wiss. Math.- Nat. Kl. (Wien) 'll: 678 (1905). Similar, but with 3 hydathodes. Appennini. S. speciosa (Dörfler & Hayek) Dörfler & Hayek in Hayek, op. cit. 677 (1905). Apical part of leaf with broad cartilaginous margin, without cilia. Flowers large. C. Italy (Appennini Abruzzesi). Plants from Spitsbergen which are perhaps assignable to the Arctic-American S. pulvinata Small , Bull. New York Bot. Gard. 2: 172 (1901), are said to be tetraploid (2n = 52).