158 Class XV. Order 11. 



erect, knobbed, tapering, smooth, ending in along beak. When 

 dry, they are striated, and abruptly contracted between the cells, 

 which are hard and somewhat bony. On cutting the pod across 

 between the seeds, it appears two celled. The seeds however 

 are contained between the laminae of the apparent partition. 



196. CARDAMINE. 



GARDAMINE PENNSYLVANIA. Muhl. American Water Cress. 



Leaves pinnate , leafets angular-toothed, obtuse. 

 Willd. 



Found in brooks and ponds, growing under water, except 

 its upper leaves and flowers. Leaves alternate, smooth, pin- 

 nate ; leafets oblong, rounded at the end, with a few large teeth 

 on each side, the terminal leafet much exceeding the rest in 

 size. The leafets in the upper leaves are entire. Flowers 

 small, white. Pods narrow, erect, an inch or more in length.- 

 Brighton. May. 



197. SISYMBRIUM. 



SISYMBRIUM NASTURTIUM. L. European Water Cress. 



Pods declining ; leaves pinnate, leafets round*, 

 ish heart shaped. Sm. 



Found in clear, fresh water, in brooks and ponds. Stems 

 spreading or floating in the water, angular, branched, rooting 

 at base. Leaves mostly immersed or floating, pinnate, the leaf- 

 ets rounded, with a few obtuse lobes or teeth. Flowers white. 

 Pods shortish, on spreading footstalks. The taste is pungent 

 and pleasant. In small ponds, Roxbury, Cambridge. June. 



198. ERYSIMUM. 

 ERYSIMUM- OFFICINALE. L. Hedge, mustard, 



"IS 



Pods pressed close to the main stalk : leaves 

 nmcinate. L. 



