CETJCIFEB^. - 95 



XV. DRABA. DRABA. 



Small annuals or perennials, usually hairy or hoary with spreading or 

 tufted radical leaves, entire or toothed, the stem-leaves few or none. 

 Flowers wliite or yellow. Filaments of the stamens \vithout appendages. 

 Pod oblong or elliptical, from one and a half to near three times as long 

 as broad, more or less flattened ; the partition broad ; the valves flat or 

 convex, their midrib usually distinct. Seeds several in each cell. Eadicle 

 accumbent on the edge of the cotyledons. 



A considerable genus, ranging over the northern hemisphere, ascending 

 to the greatest elevations and to high Arctic latitudes, and extending along 

 the great mountain chain of America into the southern hemisphere. The 

 species mostly differ from Alyssum in their longer pod, and in a peculiar 

 habit approacliing that of the Rockcresses ; from the latter genus they are 

 distinguished by the pod, which, though long for a sfliculose Crucifer, is 

 stiU much shorter, in proportion to its width, than in the shortest Rochcress. 



Flowers yellow (stiff tufted perennial) 1. Tettow D. 



Flowers white. 

 Biennials or perennials. Pedicels short and stiff. 



Stem with a few leaves, the radical ones spreading 3. Soary D, 



Stem almost leafless, the radical leaves tufted 2. Sock D. 



Annuals. Pedicels slender, spreading. 



Stem dwarf, erect, leafless. Petals deeply divided 5. Common D. 



Stem weak, ascending, leafy. Petals entire 4. WaU D. 



1. YelloTV Draba. Draba aizoides, Linn. 

 (Eng. Bot. t. 1271.) 



Stock perennial and branched, covered with closely -packed leaves, forming 

 dense tufts of 2 or 3 inches diameter. The leaves 3 or 4 lines long, sessile, 

 linear, of a bright green, edged with stiff white hairs. Peduncles leafless, 

 1 to 4 or even 5 inches high, bearing a few rather large yellow flowers. 

 Pods about 4 lines long, glabrous or shghtly hairy, with a rather long style ; 

 the valves more convex than in the rest of the genus. 



In clefts of rocks, and stony places, in the mountain districts of central 

 and southern Europe. Long cultivated in our rook-gardens, it has esta- 

 bhshed itself in considerable abundance on rocks and old walls about Pen- 

 nard Castle, near Swansea. Fl. spring. 



2. Rock Draba. Draba hirta, Linn. 

 (Eng. Bot. t. 1338. D. rupestris, Brit. Fl.) 



Stock shortly tufted and perennial, but not of long duration. Leaves 

 crowded, 3 to 5 or 6 Unes long, narrow-oblong or lanceolate, entire or 

 shghtly toothed, with a few stiff, simple or stellate hairs. Peduncles 

 usually 1 or 2 inches, and leafless ; in luxuriant specimens twice as long, 

 with one or two small ovate leaves. Flowers few and small, but larger than 

 in the hoary D. Pods 2 to 3 Unes long, on short stiff pedicels, usually 

 shghtly hoary ■with a few very minute hairs. 



In the mountains of the northern or Arctic regions of Europe, Asia, and 

 North America. Rare on some of the higher movmtain summits of Scot- 

 land. FL July. The specimens with slightly hoary pods (as are the 

 Scotch ones) ;are by some distinguished, under the name of I), rupestris, 

 from the original D. hirta of Linnaeus (not found in Britain), in which 

 they are almost or quite glabrous. 



