48 



THE CRUCIFER FAMILY. 



Auricles of the leaves rounded. Pods loosely 



spreading, valves with a prominent midrib . Eastern Erysimum. 



Ripe pods turned downwards. Plant usually hairy . 2. Tower R. 

 Plant seldom above afoot. Pod seldom 2 inches long. 



Upper leaves clasping the stem 3. Hairy R. 



Upper leaves sessile, but not clasping the stem. 



Nearly simple perennial, with erect pods ... 4. Fringed R. 



Slender branching annual, with spreading pods . 5. Thale R. 

 Stem-leaves narrowed at the base, the lower often pinnately lobed. 

 Stems nearly simple. Radical leaves hispid, in a close 



tuft 6. Bristol R. 



Stems branching at the base, in a loose tuft . . . . 7. Northern R. 



Arabis albida or grandiflora, a south Russian species or variety of 

 the A. al/pina, is common in our gardens among the early-flowering 

 perennials. The eastern Erysimum, which might be mistaken for the 

 glabrous Eockcress, is mentioned below under Erysimum, of which it 

 has the pod and seeds. 



1. Glabrous Rockeress. Arabis perfoliata, Lam. (Pig. 55.) 



{Turritis glabra, Eng. Bot. t. 777. Brit. Fl. Tower Mustard.) 



An erect annual or biennial, 2 feet or 

 more high, perfectly glabrous except a 

 few soft hairs at the very base, and 

 usually glaucous. Radical leaves spread- 

 ing but withering early, obovate-oblong, 

 sinuate or pinnately lobed, with a few 

 forked hairs. Stem-leaves oblong-lan- 

 ceolate, entire, clasping the stem by 

 pointed auricles. Flowers small, white 

 or pale straw-colour. Pods very long 

 and narrow, erect and crowded in a long 

 narrow raceme. 



On banks and roadsides and in open 

 woods, generally distributed over Europe 

 and Russian Asia, except the extreme 

 north, in northern America, and in Aus- 

 tralia. Irregularly scattered over Eng- 

 land and southern Scotland, but not re- 

 g * corded from Ireland. Fl. summer. The 



genus Turritis, which formerly comprised many species of EocJccress, 

 is still maintained by some botanists for this species and a few American 

 ones, which have the two rows of seeds rather more distinct than in 

 other JRockcr esses. 



