40 THE CRUCIFER FAMILY. [Alyssum. 



filaments, one or other of these characters being observable in all the 

 species. They have also usually a stiffer, more leafy habit, and even 

 the annuals often look woody. 



Sepals persisting round the pod. Petals minute, yellowish-white. 



Seeds 2 in each cell 1. A. calycinum. 



Sepals falling off after flowering. Petals spreading, pure white. 



Seeds 1 in each cell ... 2. A. maritimum. 



The A. incanum, often separated as a genus under the name of 

 Berteroa, having longer pods with more seeds, a common European 

 annual, has been occasionally found near Lewes and near Weymouth, but 

 does not appear to be permanently established. The yellow-flowered 

 A. saxatile, from southern Europe, is a long established perennial in our 

 rock-gardens. 



1. A. calycinum, Linn. (fig. 87). Small A. A small hard annual, 

 often simple, 3 or 4 inches high, or, when very luxuriant, branching 

 at the base, and 6 inches high. Leaves oblong-linear, much narrowed 

 at the base. Petals inconspicuous, of a pale yellow. Pods in a long 

 raceme, on short pedicels, nearly orbicular, the narrow herbaceous 

 sepals persisting round them till they are ripe. The filaments of the 

 shorter stamens have each a small fine tooth or appendage at their 

 base. 



In waste places, on the edges of fields, &c., in central and southern 

 Europe, from Sweden to the Caucasus. In Britain it occurs rarely in 

 England, Ireland, and southern Scotland. FL spring and early summer. 



2. A. maritimum, Linn. (fig. 88). Sweet A. A hard annual or 

 perennial, with much-branched procumbent or ascending stems, from 

 4 or 5 inches to near a foot long. Leaves narrow-lanceolate or linear, 

 narrowed at the base, or stalked. Flowers white with a honey scent, 

 rather small, but the petals obovate, spreading, and conspicuous. Pods 

 orbicular or slightly oval, with only one seed in each cell ; the calyx 

 deciduous. The filaments are without appendages. Kceniga maritima, 

 Br. 



In waste places and dry pastures, chiefly near the sea ; very abundant 

 .round the Mediterranean. Much cultivated in gardens, and established 

 as a weed of cultivation in some parts of England. Fl. all summer. 



XIV. DRABA. DRABA. 



Small annuals or perennials, usually hairy or hoary with spreading or 

 tufted radical leaves, entire or toothed, the stem-leaves few or none, 

 rarely many. Flowers white or yellow. Filaments of the stamens 

 without appendages. Pod oblong or elliptical, from one and a half to 

 near three times as long as broad, more or less flattened ; the partition 

 broad ; the valves flat or convex, their midrib usually distinct. Seeds 

 several in each cell. Radicle accumbent. 



A considerable genus, ranging over the northern hemisphere, ascend- 

 ing to the greatest elevations and to high Arctic latitudes, and extending 

 along the great mountain-chain of America into the southern hemisphere. 

 The species mostly differ from Alyssum in their longer pod, and in a 

 peculiar habit approaching that of Arabis ; from the latter genus they 

 are distinguished by the pod which, though long for a silicnlose 



