APRIL. 105 
coloured flowers, not many in a bunch. Leaves toothed, 
obtuse, and bristly, those of the root somewhat lyrate. Stem 
hairy, round, and leafy. Found on limestone soil. 
AraBis HIrsuTA. (Plate V. Fig. 19.) Hawry Wall-Cress. 
Leaves all bristly, toothed, those on the stem embracing it. 
Stem erect, about a foot high, stiff, leafy, and covered with 
spreading hairs. Pods straight, erect, with slightly keeled 
valves. Flowers small and white; they do not make their 
appearance till quite late in the month ; but when vegetation 
is not yet profuse we value every plant, however insignifi- 
cant in appearance. It is found on dry walls, rocks, and 
gravelly banks. There are three other species, but all rare. 
TETRADYNAMIA. SILIQUOSA. 
THALAMIFLORA. CRUCIFERZ, 
ERYSIMUM. (Treacte Mustarp.) 
Generic Character. Pod four-sided, in consequence of its pro- 
jecting ribs. Seeds rather cylindrical. Calyx equal at the base, 
not close, and falling off. 
There are only three species of this genus, none very 
striking, but one so common at this period that it must not 
be omitted, the others flower later. 
