78 FLORA OF GRAND RAPIDS. 



New i)lants are propagated by the dropjiiiig of the leaflets, or by 

 the rooting of the leatletH whicli lie close to the ground. On 

 the upper side of tlie base of the leaf, a little bud ai)pear8 which 

 forms a stem; this sends out rootlets and a new plant is formed. 



CIS. C. purpurea (Torr.) IJritton. Pur])le C'resa. 

 Wet woods; conuuon. Mid-April-Mid-May. 



Ciy. C. rhomboidea DC. Spring Cress. 

 a bulhosa (Schreb.) li.S.P. 

 Wet places; common. Mid-May. 



DENTARIA L. Tooth wort, Pkitku-root. 



620. D. dtphylla Michx. Crinkle-root. 



liich wet soil; frequent. Mid-April-Mid-May. 



621. D. laciniata Muhl. 



Moist wooded ground; common. Mid-April-Mid-May. 

 The typical form has whorled leaves, and leaflets sharply tooth- 

 ed. Growing with this are forms with alternate, rather long- 

 petioled leaves; also forms with leaves opposite. 



DIPLOTAXiS DC. 



D. MURALis DC. Sand Rocket, 

 Spontaneous on the premises of F. Skeels, corner of Jefferson 

 Ave. and Burton Ave., City. (O.H.), Summer, 

 Seeds were taken from here and sown in the Botanical Garden 

 of M.A.C. It spread rapidly and was soon found throughout 

 the Garden. 



DRABA L. Whitlow-Grass, 



622. D. Caroiiniana Walt. 

 Sandy fields; abimdant. April. 



Hillsides about Lamberton Lake; untilled ground north-east and 



south of the City. 



ERYSIMUM L, Treacle Mustard. 



E. asperum DC, Western Wall-flower, 

 A few specimens have been collected in a meadow along South 



