THE ALPINE FLORA. 



they are of easy culture in dry, sunny, open spots. All 

 are easily raised from seed or increased by division. They 

 are distinguished by the generally entire and simple leaves, 

 which are either fringed or covered with hairs ; the sepals 

 are erect and equal ; the petals entire, emarginate or bi-fid, 

 and the fruit contained in an oval silicule, the seeds being 

 without wings. The chief alpine species are: 



D. aizoides* (PI. XI). A dwarf, tufted plant, which 

 linear leaves, the edges markedly ciliate, clustering into 

 compact rosettes; flowers vivid yellow, in short racemes 

 on a leafless and smooth scape. March-July. Rocks of 

 the Alps and Jura (5oo-2ooo m.). 



D. affinis, differing by a larger flower and fruits 7 /i6 in. 

 long ( 3 /ie- 5 /i6 in. in aizoides). High Alps. 



D. Hoppeana, with leaves ciliate or fringed, something 

 like a fish-bone; flowers yellow, in a thin, sleader raceme. 

 From the granitic Alps (2200-2500 m.). 



D. tomentosa. A dwarf plant with small, cottony leaves 

 in a close rosette springing from the old withered ones; 

 flowers white; July-August. High Alps, in fissures of 

 limestone. 



D. frigida, to be known by its smooth, oblong fruits 

 (oval and ciliate in tomentosa), by somewhat smaller and 

 less white leavess. July- August. High Alps, in crevices 

 of granitic rock. 



T>. pyrenaica (Petrocallis pyrenaica) (PI. XI). A small 

 plant, forming dense tufts of innumerable rosettes of 

 leathery, glistening, cuneate leaves, strongly veined and 

 terminated at the apex by three well marked teeth. The 

 tight, compact, green cushion looks, when out of flower, 

 like a saxifrage. The lilac flowers are borne in small bunches 

 on a short stem (often non-existent). July-August: in the 

 detritus of fissures of limestone (2000-2500 m.) some- 

 thing of a "miff", requiring sandy loam on level sunny 

 rocks, and regular top-dressing. 



