66 CRUCIFER^. 



21. ERYSIMUM (Treacle-Mustard). 



1. E. cheiranthoides (Worm-seed Treacle-Mustard). 

 Leaves narrow, slightly toothed, roughish with three- 

 forked bristles ; pods erect on spreading stalks. Fields, 

 gardens, and waste places. A branched herb, 1 to 2 

 feet high, with dull green, sessile leaves, and small yellow 

 flowers with whitish sepals. FL July, August. Annual. 



* Another species, E. orientdle (HareVear Treacle- 

 Mustard), with smooth entire leaves, and cream-coloured 

 flowers, grows on some parts of the coast of Essex, Suf- 

 folk, and Sussex. 



22. CHEIRANTHUS ( Wall-flower). 

 1. C. Cheiri (Wall-flower): The only British species, 

 flourishing best on the walls of old buildings, and 

 flowering nearly all the summer, although scantily sup- 

 plied with moisture. Many beautiful varieties are cul- 

 tivated in gardens, some of which have double flowers. 

 Biennial. 



23. MATTHIOLA (Stock). 



1. M. incdna (Hoary Shrubby Stock). Stem shrubby, 

 leaves hoary with down, entire ; pods without glands. 

 The origin of the garden Stock. On the southern sea- 

 shore of the Isle of Wight, especially about Niton. 

 Flowers light purple. Fl. May, June. Perennial. 



2. M. sinudta (Great Sea Stock). Stem herbaceous, 

 spreading ; leaves oblong, downy, the lower ones imper- 

 fectly lobed ; pods rough with prickles. Sandy sea- 

 coasts of Wales and Cornwall ; flowers dull purple, 

 fragrant by night. Fl. August. Biennial. 



24. BRASSICA (Cabbage). 



1. B. campestris (Common wild Navew). Root-leaves 

 lyrate, toothed, roughish ; stem-leaves smooth, heart- 

 shaped, tapering to a point ; all somewhat glaucous. 

 Borders of fields ; common. Often confounded with 



