( 4i ) 



PLATE XXL LETTER XXIII. 

 TETRADYNAMIA. 



Sisymbrium Nafturtium. Water Crefs. 



aa7?he pinnated leaves. 



b The odd lobe ending: blunt. 

 c The corymb of flowers. 



d A fingle four-petalled cruciform flower. 



e A fingle petal. 



f The calyx. 



g The calyx, with the ftamens. 



// A fingle ftamen. 



i The iilique. 



Compare Plate XIII. See alfo Plate II. 



