58 CRUCIFER^ 



4. Hairy Bitter-cress (C. hirmki). — Leaves pinnate, without stipules ; 

 leaflets stalked and toothed, those of the root rounded and angular, those of 

 the stem nearly sessile and narrower ; pods erect. Plant annual. The long 

 pods afford a good character for this species. " The valves of these pods," 

 says Mr. Johns, in his " Flowers of the Field," " when ripe, curl up with an 

 elastic spring, if touched, and fly off, scattering the seeds to a considerable 

 distance." The number of seeds, and their ready dispersion, account for the 

 abundance of this plant, which is common everywhere, and is to be found in 

 flower all the summer, though the pods are more conspicuous than the 

 blossoms. It does not, like most of the species, confine itself to moist lands, 

 though these seem most favourable to it, as it withers much earlier in dry 

 places, dying away by the end of April. The leaves of this species, also, are 

 used as salad, and are far more agreeable in flavour than those of the Cuckoo- 

 flower. The French call the plant Le Cresson, the Germans Die Giuichblumc, 

 and the Italians Cardamindo. The plants are regarded by our continental 

 neighbours, as well as by villagers in England, as possessing great stomachic 

 virtues. Some very pretty forms are cultivated by gardeners. 



18. Rock Cress (Arabis). 



1. Thale-cress, or Rock-cress (A. thalidna). — Leaves oblong, some- 

 what toothed, hairy ; root-leaves slightly stalked ; stem branched ; pods 

 angular, twice as long as their stalk. Plant annual. This is a very common 

 little herb on dry walls, bearing small white flowers from May to July. 

 The stem is seldom more than six inches high. It is called in France 

 L'Arabette, and in Germany, Der Gdnsekraut. The Dutch term this, or another 

 of the species, Honigschub, and it is the Arabide of the Spaniard. De Theis, 

 in order to account for its botanical name, as well as that by which it is 

 familiarly known in some countries, supposes that the plant is a native of 

 Arabia, but this is a forced and improbable explanation. Some authors 

 include this in the genus Sisymbrium. 



2. Hairy Rock-cress (A. hirsMa). — Leaves all hairy and toothed; stem- 

 leaves clasping, heart-shaped at the base, and numerous ; pods erect and 

 straight. Plant biennial. The Hairy Rock-cress is a stifi" rigid plant, common 

 on walls, rocks, and banks, in England and Scotland. It is about a foot in 

 height, and bears small white flowers during June and July. 



3. Alpine Rock-cress {A. petrcea). — Root-leaves pinnatifid and stalked, 

 with smaller lobes at their base; stem-leaves nearly entire, and sessile. 

 Plant perennial. This species is found on the rocks of Scotland and Wales. 

 It has white flowers, tinged with purple, Avhich are rather larger than those 

 of the Hairy Rock-ciess, and it blooms from June to August. It is frequent 

 on the high mountains of the west and north of Scotland, and is a slender 

 plant, from four to six inches in height, sometimes quite smooth, but usually 

 more or less hairy. 



4. Fringed Rock-cress {A. cilidta). — Leaves somewhat toothed, oval, 

 smooth, and fi'inged with minute hairs ; root-leaves obtuse, and nearly sessile ; 

 those of the stem either roundish at the base, or clasping ; pods nearly erect. 

 Plant biennial. The small white flowers of this species, which is rare, may 



