851 



ducting tissue, are comparatively rare ; but a very striking instance, 

 perhaps even more curious than that which occurs in Statice, is pre- 

 sented in the plant about to be discussed. 



b a 



ha d 



7 c 



8 d 



U 



11 



10 



Nuphar lutea. 



Fig. 4. — Section of ovule at the time of fecundation, a. The primine. 6. Secundine. c Embryo-sac. 

 e. Funiculus. 



Fig. 5. — Section of the same, in an advanced state, showing the primary utricle (c.) at the summit of the 

 filiform embryo-sac. d. The nucleus. 



Fig. 6. — Primary utricle of the last, highly magnified. 



Fig. 7. — Embryo-sac removed from the surrounding parts, in an earlier stage than it is seen at fig. 5. 



Fig. 8. — Embryo-sac, primary utricle (e), and the nascent embryo {d) in a more advanced stage. 



Fig. 9. — Section of the embryo when nearly ripe, showing its dicotyledonous structure. 



Nymphcea alba. 



Fig. 10. — Ovule at the time of fecundation, a. Primine. J. Secundine. e. The funiculus, which after- 

 wards develops itself into an arillus. 



Fig. 11.— Section of ditto, showing the embi-yo-sac and the primaiy utricle (c). 



4c 2 



