SPECIES AND VARIETIES. 195 



entire lobes ; flowers small, yellow, the raceme close ; pods 

 patent, straight. — Waste places. Fl. May to August. [See 

 also p. 45.] 



(24) Turritis. Tower Mustard. 



T. glabra : annual or biennial ; stem two feet or more high, 

 erect, glabrous except a few hairs at the base, usually glau- 

 cous; leaves spreading, obovate-oblong, sinuate or pinnately 

 lobed, with a few forked hairs, the upper ones oblong-lanceo- 

 late, entire, clasping the stem by pointed auricles; flowers 

 small, white or straw colour ; pods long, narrow, erect, crowded 

 in a long narrow raceme. — Banks and roadsides. Fl. June. 



(25) Arabis. Rock-cress. 



* Stem-leaves undivided, rounded or auricled at the base. 



A. hirsuta : annual or biennial ; stem a foot high or more, 

 rather stiff", erect, usually simple, rough with short hairs ; 

 leaves spreading, obovate or oblong, slightly toothed; stem- 

 leaves erect, oblong or lanceolate, all, or the upper ones, clasp- 

 ing by short auricles ; flowers small and white ; pods slender, 

 1-2 inches long, erect, crowded in a long raceme. — Walls, 

 banks, and rocks. Fl. May, June. 



** Stem-leaves narrowed at the base. 



A. petrsea : stems branched at the base, loosely tufted, al- 

 most creeping, but seldom above six inches long ; lower leaves 

 obovate or oblong, stalked, mostly pinnately divided, with the 

 terminal lobe largest, some of them nearly entire, the upper 

 ones few, narrow, almost entire ; flowers few, white or slightly 

 purplish ; pods spreading, rather more than half an inch long. 

 — Moist mountainous places. Fl. July. [See also p. 45.] 



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