Draba
(Greek name used by Dioscorides, from drabe, acrid; referring to the taste of the leaves). Whitlow Grass. Including Petrocallis. ORD. Cruciferoe. More than 150 species have been described; but it is probable that not more than half that number are really distinct. Perennial or annual branched herbs, which are sometimes tufted, sometimes elongated, smooth or pilose, or usually velvety from soft branched hairs. Flowers white or golden, rarely pink or purple; racemes terminal; pedicels filiform, bractless. Leaves linear, oblong or ovate, entire or toothed. "Amongst the spring - flowering alpines," says Mr. Robinson, "the genus Draba must always take an important position. In addition to the brilliant golden colour of the flowers of one section of the genus, the plants are characterised by a dwarf compact habit, and by much neatness in the arrangement of the bristly ciliated hairs, which not unfrequently become bifurcate; thus the attractive appearance in the matter of colour is enhanced, on a closer inspection, by the beauty of form and detail. In another section, we find white to be the predominant colour; and though in many cases the flowers are small, still, in the mass, filling up a nook or crevice in a rockwork, and contrasted with the dark green leaves, they become very effective. They should be placed in the sunniest aspect on a rockery; the more effectually the plants are matured by the autumn sun, the more freely will they return these favours by an abundant bloom in early spring. The perennials may be propagated by dividing at the roots; the annuals or biennials by seeds, which should be sown in ordinary garden soil, in the open border, in spring. Many of the strictly annual species may be made biennial by sowing seeds too late to allow the plants to flower the first season. Perennials, except where otherwise stated.
D. aizoides (Aizoon-like).* fl. yellow; scapes naked, smooth; stamens about the length of the petals. March. l. lanceolate-linear, keeled, ciliated. h. 2in. to 3in. Europe (South Wales). (Sy. En. B. 138.) D. Aizoon (Aizoon).* fl. bright yellow; scapes naked, villous. April. l. linear, acutish, keeled, stiff, ciliated. h. 3in. Mountains of Western Europe, 1819. SYN. D. ciliaris.
D. alpina (alpine).* fl. golden-yellow, a little smaller than those of D. aizoides; scapes naked, pubescent. April. l. lanceolate, flat, pilose, with branched hairs. h. 3in. Northern Europe, 1816.
D. aurea (golden). fl. yellow; petals obovate, blunt, clawed. May. l. oblong-linear, acute, entire, pubescent. Stem leafy, somewhat branched, velvety. h. 6in. Greenland, 1824. Biennial. (B. M. 2934.) D. bruniifolia (Brunia-leaved). fl. yellow; petals twice the length of the calyx and stamens; scapes naked, pubescent. June. l. linear, somewhat keeled, ciliated, acute, loosely rosulate. h. 4in. Caucasus, 1825. Plant loosely tufted. (R. G. 780.) D. ciliaris (hair-fringed). A synonym of D. Aizoon.
D. cinerea (grey). fl. white. Early spring. l. oblong-linear, entire; stem leaves five or six, entire, scattered. Stem leafy, somewhat pubescent. h. 3in. to 6in. Siberia. 1820. Biennial.
D. cuspidata (cuspidate). fl. yellow; scapes naked, villous. Spring. l. linear, acutish, keeled, ciliated. h. 3in. Tauria, 1821. Closely allied to D. Aizoon.
D. glacialis (icy).* fl. bright golden-yellow; scapes naked, covered with starry pubescence. May. l. linear - lanceolate, entire, hispid with stellate hairs. h. 2in. Siberia, 1826. Closely allied to D. aizoides, but differing from it in having a fewflowered stem, and pedicels which are shorter than the pod.
D. lapponica (Lapland). fl. white; scapes naked, very smooth. May. l. lanceolate, quite entire, rather pilose. h. 2in. or 3in. Alps of Lapland, 1824.
D. Mawii (Maw's).* fl. 3/4in. in diameter; sepals very concave, bristly at the back, green, tipped with red-brown; petals three times as large as the sepals, obovate - cuneate, retuse, spreading, quite white. Spring. l. linear-oblong, obtuse, shining; margin pectinate, with rigid incurved or spreading bristles; under surface with a prominent midrib. Spain, 1873. An excellent rock plant, forming low densely - tufted bright-green patches. (B. M. 6186.) D. nivalis (snowy).* fl. white; scapes naked or one-leaved, smooth. April. l. oblong-linear, ciliated, and somewhat pilose. h. 1in. or 2in. Arctic Europe, 1820. Habit more compact than D. lapponica.
D. pyrenaica (Pyrenean). Rock Beauty. fl. at first white, afterwards changing to purple; scapes naked. May. l. cuneiform, palmate, three-lobed. h. 2in. to 3in. Mountains of South Europe. SYN. Petrocallis pyrenaica. (B. M. 713.) D. Sauteri (Sauter's). fl. yellow; scapes smooth. Spring l. spathulate, stiff, ciliated. h. 4in. Switzerland.
D. tridentata (three-toothed). fl. yellow; scapes naked, smooth. August. l. obovate, narrowed at the base into the petiole, threetoothed at the apex, hairy. h. 3in. Caucasus, 1838.
D. violacea (violet).* fl. deep violet-purple. l. opposite, ovate, downy. Stem suffruticose, branched, diffuse. h. 6in. to 12in. Quito Andes, 1867.