164 ENGLISH BOTANY. 
the rest of the genus. Plant greyish green, with scattered simple 
forked and trifurcate hairs. 
This plant is placed by many botanists in the genus Sisym- 
brium, on account of the position of the radicle agreeing with the 
character of that genus rather than with Arabis; the habit, 
however, is much more that of Arabis, and the cotyledons are 
occasionally accumbent in A. Thaliana, although usually incumbent. 
In a few pods I have found both forms of embryo, though the 
accumbent cotyledons are rare. 
Thale Cress, Common Wall Cress, Turkey Pod. 
French, Arabetie de Thalle. 
SPECIES I1—ARABIS PETRA. Lamarck. 
Puate CXITI.* 
A. Crantziana, Reich. Ic. Fl. Germ. et Helv. Vol. II. Tetr. Tab. XXXIV. Fig. 4323 4 
A. Crantziana, Hhrh. Herb. 78. 
A. hispida, Linn. fil. Sm. Eng. Fl. Vol. IIT. p. 211. 
Cardamine petrea, Linn. Sp. Pl. p. 913. 
C. hastulata, Sm. Eng. Bot. No. 469. 
Rootstock slender, branched, woody. Jadical leaves sub-lyrate, 
pinnatifid or spatulate, toothed, the base attenuated into a leaf stalk ; 
stem leaves spatulate, toothed, or strap-shaped, entire, attenuated 
at the base, not amplexicaul. Petals obovate, twice as long as the 
sepals, slightly spreading. Pods spreading, about twice or thrice 
as long as the pedicels; valves l-nerved; style short, cylindrical. 
Seeds elliptical-ovoid, compressed, with only a rudimentary wing 
at the extreme apex. 
On alpine rocks and rocky débris in North Wales, and the 
Scottish mountains. It occurs in the Island of Harris in the 
Hebrides, in Sutherland, and even at Baltasound in Shetland; but 
it is most common on the mountains of Braemar, and in Aber- 
deenshire it is frequently to be found on the banks of the Dee to 
within a few miles of Aberdeen, no doubt carried down by streams 
from the higher localities. It is also found in Ben Bulben, 
Ireland. 
England, Scotland, Ireland. Perennial. Summer, Autumn. 
Rootstock dividing into several short branches, each of which 
produces a rosette of leaves. Stems 4 to 8 inches high, ascending, 
usually flexuous. Radical leaves more or less distinctly stalked, and 
* The Plate is E. B, 469, unaltered. 
