Sisymbrium CRUCIFERAE Rorippa 



S. altissimum L. Tumble Mustard. 



Rare weed on roadsides: along causeway south of Wilmington, 

 Commons, 6 July 1898 (A, D) ; along Duncan's road, Marshallton 

 (NC), Otis, 30 May 1916 (A). Nat. from Europe. 



Arabidopsis (DC) Schur. 



A. Thaliana (L.) Schur. (Sisymbrium Thalianum of Gray's Man., 

 ed. 7.) Mouse-ear Cress. 

 Frequent throughout, in fields, open woods and waste ground. 

 Mid-April, May. Nat. from Europe. 



Hesperis L. Rocket. 



H. matronalis L. Dame's Violet. 



Occasional escape from gardens to waste ground. New Castle 

 County. Introd, from Europe. 



Erysimum L, 



E. cheiranthoides L. Worm-seed Mustard. 



Rare: bank of Brandy wine Creek at Wilmington, E. Tatnall in 

 1841 (D); waste ground, Wilmington, Commons, 18 June 1897, (A). 



E. repandum L. 



One collection: Tarbutton Pond, n. e. of Trappe (Ta), Earle, 

 2401, 11 May 1940 (P). Adv. from Europe. 



Nasturtium R. Br. 



N. officinale R. Br. {Sisymbrium Nasturtium-aquaticum L.) 

 Water Cress. 

 Frequent in ditches and slow streams. June. Nat. from Europe. 



Rorippa Scop. 

 R. sylvestris (L.) Bess. (Radicula sylvestris (L.) Druce.) 



Infrequent; fields, roadsides and meadows. New Castle and 

 Cecil Counties. June, mid-July. Nat. from Europe. 



R. islandica (Murray) Borbas var. microcarpa (Regel) Fernald. 



{R. palustris (L.) Moench. See Rhodora 42, 271-274. 



1940.) Marsh Cress. 

 Frequent in wet places in the northern half of the Peninsula. 

 May into autumn. 



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