PLATE XXI. LETTER XXIII. 
TETR ADYNAMIA. 
Sisymbrium Nasturtium. fVater Cress. 
a a The pinnated leaves. 
b The odd lobe ending blunt. 
c The corymb of flowers. 
d A single four-petalled cruciform flower. 
e A single petal. 
f The calyx. 
g The calyx, with the stamens. 
h A single stamen. 
i The silique. 
Compare Plate XIII. See also Plate II. 
