48 CRUCIFERyE 



with a flat, two-edged, sword-like beak. — Waste ground.- — Fl. June, 

 July. Annual. Seedlings of this species are largely eaten, with 

 those of Cress {Lepidiimi sativum)^ as salad. 



14. DiPLOTAXis (Rocket) has spreading sepals ; but differs from 

 the mustards in its flattened pods with membranous valves and 

 seeds in two rows. (Name from the Greek dip/os, double, taxis, 

 rank or row.) 



1. D. temiifblia (Wall Rocket). — Slender, branched, i — 2 feet 

 high ; steJH woody below ; leaves deeply divided into long narrow 

 segments, glaucous ; flowers \ in. across, light yellow, fragrant ; 

 pods short, linear, erect, on very long slender stalks. — On old 

 walls. — Fl. June — September. Perennial. 



2. D. murdlis (Sand Rocket), a less branched, hispid, herba- 

 ceous, and generally annual species, grows in waste ground, 

 especially near the sea. 



^15. Alyssum, a genus of small plants, mostly hoary with 

 adpressed hairs, with simple leaves, small white or ^^q\^ flo2ve7's, 

 and rounded, few-seeded pods, includes three alien species, 

 sometimes naturalised : A. incdnum, A. alyssoides, with stellate 

 hairs ; yeWow flozvers, and persistent sepals; and A. viaritimum, 

 with bi-partite hairs ; white, sweet-scented _//^z£;^?'i, and deciduous 

 sepals. 



16. Draba (Whitlow-grass). — Small herbs, mostly perennial 

 and hoary with stellate hairs \ leaves small, simple, the radical 

 ones in a rosette ; flowers small, white or yellow ; pods compressed 

 or turgid. (Name from the Greek drabe, acrid.) 



* Flowers white 



1. D. murdlis (Speedwell-leaved Whitlow-grass). — Stem leafy, 

 branched, about a foot high ; leaves rough, with stellate hairs, 

 egg-shaped, blunt, toothed, embracing the stem ; pedicels spreading 

 horizontally. — Limestone hills in the west of England ; rare. — 

 Fl. April, May. Annual. 



2. D. i^icdna (Twisted Whitlow-grass). — Stem leafy, branched, 

 4 — 14 in. high; leaves hoary with stellate down, lanceolate, 

 toothed ; /^?^^ twisted. — Mountains, and sandhills near the sea; 

 uncommon. — Fl. June, July. Perennial. 



3. D. rupestris (Rock Whitlow-grass). — Stems several, i — 2 in. 

 high, almost leafless ; leaves rosulate, stellately pubescent, ciliate. 

 — In crevices of the rocks and among moss on the summits 

 of some Highland mountains; very rare. — Fl. July, August. 

 Perennial. 



