224 Karl M. Wiegand and Arthur J. Eames 



1. Draba (Dill.) L. 



a. Petals deeply 2-cleft; plant annual, 2-12 cm. high; fruit obtuse, straight; stigma 



subsessile. 1. D. vcrna 



a. Petals entire; plant perennial, 15-45 cm. high; fruit acutish, twisted; style about 



0.5 mm. long. 2. D. arabisans 



1. D. verna L. Whitlow Grass. 



A weed of dry sandy or gravelly paths and slopes, in soils not strongly calcareous ; 

 rare. Apr-May 15. 



Cemetery, University Ave., Ithaca, 1878 (Prof. A. N. Prentiss, D.l), still per- 

 sisting below the tool house; wild, s. bank of Big Gully, 1882 (D.). 



E. Alass. to Minn., southw. to Ga. and Tenn. Naturalized from Eurasia. 



2. D. arabisans Michx. 



Damp or dry shale ledges and crests, in limy situations ; rare. May 20-June 10. 



First small ravine n. of McKinney Twin Glens, 1881 (£>.!), still persisting; Esty 

 Glen, along the brook just above the falls, 1871 (D.), 1918!, and edge of woods just 

 s. of falls, 1916 !. Reported from only about five other stations in N. Y., one being 

 in Erie Co. and the others all in the northern part of the State. 



Lab. and Newf. to Ont., southw. locally to Me., Vt., and N. Y. A northern species. 



2. Berteroa DC. 

 1. B. incana (L.) DC. 

 Dry soil ; rare. July 15-Aug. 



Well established on roadside bank, between West Danby and North Spencer, 1920. 

 Me. to Minn., southw. to N. J. and Mo. Introduced from Eu. 



3. Alyssum (Tourn.) L. 

 1. A. alyssoides L. (A. calycinum of Cayuga Fl.) 



A weed in dry gravelly or sandy open places ; rare. May 20-June 20. 



President White Place, C. U. campus, 1878 (Prof. Prentiss, D.) ; "along the road 

 near the Jayne Place" (corner University Ave. and Lake St., Ithaca), 1879 (F. H. 

 Severance, D.) ; Fiske-McGraw (Chi Psi) grounds, 1881 (P. L. Kilbomc, D.) ; 

 Lake St., Ithaca, near the gun works, where it has grown for many years. 



N. H. and Ont., to Iowa, southw. to Mass. and N. J., also in the Far West. 

 Naturalized from Eu. 



4. Thlaspi (Tourn.) L. 

 1. T. arvense L. Penny Cress. French-weed. 



A weed in cultivated ground and waste places, in gravelly soils ; infrequent. May 

 20-June. 



E. State St. and Harvard Place, Ithaca; Agricultural College campus, in several 

 places; C. U. poultry farm n. of Forest Home; McKinneys; Myers Point. 



Que. to Man., southw. to N. Y. and Kans. ; common in Canada. Naturalized from 

 Eu. 



5. Lepidium (Tourn.) L. 



a. Cauline leaves not clasping ; plant nearly or quite glabrous. 



b. Petals present ; pubescence of inflorescence composed of curved acute hairs ; 

 rosette leaves lyrate-pinnatifid ; embryo accumbent; pods 2.5-3.1 mm. wide. 



1. L. virginicutn 

 b. Petals absent ; pubescence of inflorescence composed of minute stiff divaricate 

 blunt hairs ; embryo incumbent. 

 c. Pods oval or obovate, 1.7-2.5 mm. wide; rosette leaves deeply incised-lobed, 

 the lobes outcurved. 2. L. densiflorum 



