26 



51. Aquatic herbs, with lower leaves opposite and finely divided, 

 immersed. Upper leaves alternate, floating, shield-like, oval or 

 round, entire. Embryo in a membranous sac or vitellus. 



CABOMBACEJB. 

 Rarely growing in water. Embryo not in a vitellus. 



Tropical trees or shrubs. Leaves alternate, simple, entire. Calyx 

 three parted. Corolla six petalled. Filaments very short. 

 Seeds with a mottled albumen. ANONACE;E. p. 43. 



Herbs, or rarely shrubs. Leaves mostly more or less divided. 

 Seeds with a homogeneous albumen. 



Sepals two. Petals four, one or two sac-like or spurred. 



FUMARIACEJE. p. 49. 



Sepals more than two. Petals rarely spurred, and when so either 

 all alike or inclosed in spurred sepals. RANUNCULACEJJ. p. 33. 



52. Aquatic. Placentae covering the dissepiments. 



NTMPU^ACE^. p. 46. 

 Not aquatic. Placenta in the axis. 54 

 Placentae parietal. Rarely growing in water. 



Stamens six tetradynamous, four long and two short. Petals four, 



arranged cruciform. CRUCIFER.E. p. 51. 

 Stamens not tetradynamous. 



Disc at the base of the flower small or none. 53 

 Disc large. 



Stigma undivided. Fruit closed at the apex. 



CAPPARIDACE.E. p. 56 

 Stigma lobed. Fruit open at the apex. RESEDACE^E. p. 57. 



53. Sepals three, soon falling off. Fruit a many-seeded capsule or 



pod. Stigmas three or four, sessile. PAPAVERACEJE. p. 48. 

 Calyx five or six parted or leaved. 



Capsule included in the persistent calyx tube. FRANKENIACEJS. 

 Fruit not included in a persistent calyx. 



