Cochlearia.] VI. CRUCIFERffl. 39 



Tall erect plant, with very large oblong radical leaves . 1. C. armoracia. 



Low diffuse plant, the leaves small and thick . . . . 2. C'. officinalis. 



1. C. armoracia, Linn. (fig. 85). Horseradish. Bootstock tapering 

 inU a long root. Radical leaves on long stalks, often 6 inches to a 

 foot long, and 4 to 6 inches broad, sinuate and toothed at the edges, 

 glabrous, but rough. Stems 2 to 3 feet high, erect ; the leaves smaller 

 and narrower than the radical ones, the lower ones often deeply toothed 

 or almost pinnatifid. Flowers small and white, in numerous racemes, 

 forming a terminal panicle. Pods on slender pedicels, ovoid or elliptical, 

 without any prominent nerve. Armoracia rusticana, Rupp. 



A plant of south-eastern Europe, introduced by cultivation into 

 northern and western Europe. It is naturalised in several parts of 

 Britain. Fl. summer. The pod seldom comes to perfection in this 

 country. 



2. C. offlcinalis, Linn. (fig. 86). Scurvy-grass. A low, diffuse, quite 

 glabrous, and somewhat fleshy annual or biennial, the stems seldom 

 above 6 inches long. Lower leaves stalked, orbicular, deltoid, or reni- 

 form, entire or angularly toothed ; the upper ones sometimes similar, 

 sometimes ovate or oblong, and often quite sessile. Flowers in short 

 racemes, the petals obovate and spreading. Pods globular or ovoid, 

 varying from 2 to 3 lines in diameter, pointed by the short style, the 

 midrib of the valves very prominent when dry. C. polymorpha, Syme. 



In stony, muddy, or sandy soils, in the Arctic Circle, on the sea- 

 coasts of northern and western' Europe, and at considerable elevations 

 in the great mountain-chains of Europe. Not uncommon on the shores 

 of England and Ireland, still more abundant on those of Scotland, 

 penetrating inland along some of its rivers, and in the Highland 

 mountains. Fl. all summer. It varies much in the size and shape of 

 the leaves, in the size of the flowers, and the size and shape of the 

 pods, and has been divided into many species. [The most prominent 

 forms are 



a. C. ojficinalis proper. Root-leaves orbicular or reniform, deeply 

 cordate, pods nearly globose. 



b. C. alpina, Wats. Leaves as in a, pods narrowed at both ends. 

 C. grecnlandica, Sm. Mountains. 



c. C. danica, Mill. Leaves deltoid, pods as in b. 



d. C. anglica, Linn. Much larger in all Its parts. Leaves oblong- 

 homboid or ovate, not cordate, pods inflated, constricted at the 

 suture.] 



XIII. ALYSSUM. ALYSSUM. 



Annuals or low branching perennials, with a hoary or short stellate 

 down, and white or yellow flowers. Filaments of the stamens, or the 

 shorter ones only, usually winged near the base, or thickened, or 

 furnished with small teeth. Pod sessile within the calyx, orbicular 

 or oval, the partition broad, the valves convex, and not veined. Seeds 

 1 to 4, or very rarely more, in each cell. Radicle accumbent on the 

 edge of the cotyledons. 



An extensive genus, in Europe and northern Asia, and tolerably 

 natural, distinguished from Draba chiefly by the short few-seeded pod, 

 with more convex vajves, or by the appendages to the base of th 



