~ 
30 THE ORUCIFER FAMILY. [Arahis. 
3, 4. hirsuta, Br. (fig. 58). Hairy Rockcress.—A rather stiff erect 
annual or biennial, attaining a foot or rather more in height, but often 
shorter, usually simple, and rough with short hairs. Radical leaves spread- 
/ 
Pee 
ing, obovate or oblong, slightly toothed; stem-leaves generally erect, oblong — 
or lanceolate, all, or at least the upper ones, clasping the stem by short 
auricles. Flowers small and white. Pod slender, 1 to 2 inches long, 
erect and crowded in a long raceme. Seeds without any wing. A. 
sagittata, DC. 
On walls, banks, and rocks, common in the greater part of Europe and 
Russian Asia, but not in high northern latitudes. Not an abundant plant 
in Britain, although occurring in numerous localities, even in the north of 
Scotland. FV. summer. [Var. glabrata, Syme, has nearly glabrous leaves. | 
4, A. ciliata, Br, (fig.59). ringed Rockeress.—Very near A. hirsuta, 
but not above 6 inches high; the stem usually glabrous, and the leaves 
only fringed with a few stiff hairs on their edge, the upper ones rounded at 
the base and not auricled, The flowers are rather larger, and the pods less 
erect. 
In stony and rocky places, in the mountains of central Europe. In Britain, 
only at a few stations in 8. Wales and the west coast of Ireland. Fl. summer. 
There is some doubt whether the Irish and the Continental plants are the 
same; but probably both are mere varieties of the common A. hirsuta. 
5, &. Thaliana, Linn. (fig. 60). Zhale Rockeress, Thalecress. Wall- 
eress.—A slender, erect, branching annual, usually about 6 inches high, but 
sometimes attaining a foot, clothed with short, spreading stiff hairs, or 
sometimes nearly glabrous. Leaves mostly radical and spreading, oblong, 
with a few coarse teeth, from + tol inch long. Stem-leaves few, small, 
and sessile. Flowers small and white. Pod on spreading pedicels, in 
slender racemes, narrow linear, varying from 4 or 5 inches long to 
twice that length. Seeds small, the two rows blended into one; the 
cotyledons placed obliquely, so that the radicle is almost incumbent on the 
back of one of them. Sisymbrium Thaliana, Hook. 
On old walls, dry banks, and stony waste places throughout Europe and 
Russian Asia, extending into northern America. Frequent in Britain. 
Fil. early spring, and occasionally also in summer and autumn. On account 
of the position of the radicle, this species is referred by some to Sisymbrium, 
with which it has little else in common. 
6, A. stricta, Huds. (Fig. 61). Bristol Rockcress.—A perennial, but 
probably of few years’ duration, resembling in some respects the A. petrea. 
Radical leaves in a small spreading tuft, pinnately lobed, and hispid with 
stiff hairs. Stems about 6 inches high, erect, nearly simple, with a very 
few small leaves narrowed at the base. Petals narrow and erect. Pod 
erect, about an inch long. 
The Continental distribution of this species is uncertain, as the name is 
often given to plants quite different from ours; but it appears to be a 
native of limestone rocks in the mountains of western Europe. In Britain, 
only on St. Vincent’s rocks, near Bristol, where it is getting very scarce, 
and it will probably soon have to be expunged from our Floras. Fl. spring. 
7. &. petreea, Lam. (fig. 62). Northern Rockcress.—A small perennial, 
in some respects intermediate between Arabis and Cardamine. Stems 
branched at the base, loosely tufted, or shortly diffuse, or almost creeping, 
