Rorippa 



Cruciferae 



495 



o 50 



Map 1017 

 Rorippa palustris 

 izv. hispida (Desv) Rydb. 



o 53 



Map 1019 



Nasturtium officinale R. Br. 



1. Rorippa sessiliflora (Nutt.) Hitchc. (Radicula sessiliflora (Nutt.) 

 Greene.) Sessile-flowered Cress. Map 1015. Infrequent but usually 

 frequent to common where it is found. It inhabits muddy places and is 

 often found on the borders of sloughs, ponds, and streams, usually after 

 the water in them has been lowered by dry weather. Also found in low, 

 flat, fallow fields. It is usually frequent on the muddy slopes of the Ohio 

 River and, no doubt, in such a habitat it probably could be found in all of 

 the Ohio River Counties. 



Va. to Nebr., southw. to Fla. and Tex. 



2. Rorippa palustris (L.) Bess. var. glabrata (Lunell) Vict.* (Radicula 

 palustris (L.) Moench.) Yellow Watercress. Map 1016. Infrequent to 

 frequent or even common in all parts of the state. It seems to have no 

 preference for sun or shade and grows in wet places along streams, about 

 ponds, lakes, and sloughs, and in ditches and fallow fields. 



Throughout N. A. except the extreme north ; also found in Eurasia. 



2a. Rorippa palustris var. hispida (Desv.) Rydb.f (Radicula palustris 

 var. hispida (Desv.) Rob. and Radicula hispida (Desv.) Britt.) Hispid 

 Yellow Watercress. Map 1017. Infrequent mostly throughout the 

 northern part of the state although it was collected by Coulter in Jefferson 

 County. It has the habitat of the preceding species but grows in much 

 wetter places. 



Throughout temperate N. A. ; also in Eurasia. 



3. Rorippa sylvestris (L.) Bess. (Radicula sylvestris (L.) Druce.) 

 Creeping Yellow Watercress. Map 1018. Local or infrequent on the 

 alluvial bottoms of streams throughout the state except along the muddy 

 slopes of the bank of the Ohio River where it is frequent to common. This 

 is a pernicious weed and should be destroyed as soon as it is discovered. 

 It is best exterminated by the application of some reliable weed killer. 



Newf. to Ont. and Mich., southw. to Ala. and 111. 



* The latest name proposed for this plant is Rorippa islandica var. Fernaldiana But- 

 ters & Abbe. (Rhodora 42: 28. 1940.) 

 •j-The latest name proposed for this plant is Rorippa islandica var. hispida (Desv.) 



Butters & Abbe. (Rhodora 42: 26. 1940.) 



