IN'ASTURTIUM. 



95 



characteristics, both of organic structure and chemical composition, than 

 this ; and hence to know a single plant of the family well — for example, 

 mustard — is to know them all. Many of them — for instance, the cabbage 

 and turnip — have been modified to a considerable extent by long cultiva- 

 tion, and have become valuable articles of food. 



NASTURTIUM. 



Character of the Genus. — Pod a silique or silicle, linear-oblong or glob- 

 ular, nearly or quite round. Seeds small, numerous, marginless, in two 

 iri-egular rows in each cell. Cotyledons accumbeut. Annual, biennial, or 

 perennial herbs, aquatic or growing in marshes and wet places, with white 

 or yellow flowers, and com- 

 monly smooth, shining, pin- 

 nate or piunatifid leaves. 



Nasturtium officinale 

 Robert Brown. — M'ater-cress. 



Description. — Calyx : se- 

 pals ovate, caducous. Co- 

 rolla : petals white, twice the 

 length of the sepals. Siliques 

 one-half to two-thirds inch 

 long, bending upward, more 

 or less, on divergent, ascend- 

 ing pedicels, of nearly the 

 same length. Root biennial, 

 long, and creeping. Stem 

 spreading and rooting. 

 Leaves pinnate ; leaflets 3 to 

 11, roundish or oblong, near- 

 ly entire, the terminal one 

 largest. 



Habitat. — Introduced fi'om 

 Europe, where it has long been cultivated as a salad. Escaping from cul- 

 tivation here, it has become established in brooks and ditches. 



Nasturtium Armoracia Fries {GochleariaArmoraciaJjmnd).— Horse- 

 radish. 



Description.— Calyx : sepals ovate, obtuse, caducous. Corolla : petals 

 white, twice the length of the sepals. Style very short, persistent. Pod 

 nearly globular, about 4-seeded, seldom attaining perfection here or in 

 Britain. Root perennial, large, tapering, 6 to 12 inches long. Stem erect, 

 2 to 3 feet high. Radical leaves long and large, crenate, seldom piunat- 

 ifid : stem-leaves smaller and narrower than the radical, the lower ones 

 7 



Fig. 107. — Nasturtium officinale. 



