86 Tennessee Flora; 



THLASPI L. 



Thlaspi arvense L. Field penny cress. In the grounds of 

 market gardens, introduced with seeds. Summer. 



SISYMBRIUM L. 



Sisymbrium officinale L. Hedge mustard. Waste places.. 

 O. S. Introduced from Europe. May-November! 



SINAPIS L. 



Sinapis alba L. White mustard. Escaped from cultiva- 

 tion. Native of Europe. Summer. 



BRASSICA L. 



Brassica nigra (L.) Koch. Black mustard. In cultivation 

 and escaped. 



B. arvensis (L.) B. S. P. Sinapis arvensis L. Charlock. 

 Wild mustard.' 



B. campestris L. ~ Turnip. Cultivated in many varieties. 

 Summer. 



B. Rapa L. var. depressa. Flat-top turnip. In cultivation. 



B. Napus L. Rape. Formerly cultivated for the oil of the 

 seeds, butnow abandoned. 



B. oleracea L. Cabbage. Cultivated in many varieties. 

 Summer. 



RAPHANUS L. 



Raphanus sativus L. Garden radish. Cultivated in many 

 varieties, and sometimes spontaneous. Native of Asia. June- 

 October. 



R. Raphanistrum L. Appears sometimes as a garden weed,, 

 introduced with other seeds. "Jointed charlock." Summer. 



lODANTHUS Torr. & Gray. 



lodanthus pinnatifidus (Michx.) Steudal. ' Thelipidium 

 pinnatifidum S. Watson. Damp woodlands. O. S. May, 

 June. 



RORIPA Scop. (Nasturtium R. Br.) 



Roripa palustris (L.) Bess. Nasturtium palustre DC. 

 March water cress. Knoxville. A. Ruth. May-August. 



R. sessiliflora (Nutt.) A. S. Hitchcock. Nasturtium sessili- 

 florum Nutt. Wet m^dows and ditches'. O. S. April- June. 



R. Nasturtium (L.) Rusby. Nasturtium officinale R. Br. 

 Water cress. In brooks and streams. O. S. Also sometimes 

 cultivated. Naturalized from Europe. April-November. M. 



R. Armoracia (L.) A. S. Hitchcock. Nasturtium Armora- 



