EXPLANATION OF THE PLATES. 
559 
Fig. 14, The same, divided perpendicularly; a, stigma; b, indusium. 
Fig. 15. Stigma of Banksia coccinea, with a part of the style, after Ferdinand 
Bauer. 
Fig. 16. The earliest state of the ovula of Cucumis anguria ; this, and the 
succeeding figures, to 25 inclusive, are after Mirbel. 
Fig. 17. Three of these ovules in a more advanced state. 
Fig. 18. An ovulum at the period when the apex of the nucleus a is just appear- 
ing through the primine. The foramen has already become oblique with respect 
to the apex of the ovulum. 
Fig. 19. An ovulum of the same, at the period when the secundine is appearing 
through the foramen ; a, nucleus ; 6, border of secundine ; the nucleus is now 
more oblique than before. 
Fig. 20. An ovulum of the same, at a subsequent period, but still long before the 
expansion of the flower ; the several parts are more developed ; the nucleus, 
which at first was terminal, has now become lateral, and is evidently turning 
towards the base of the ovulum : a, nucleus ; b, border of secundine. 
Fig. 21. An ovulum of the same after fertilisation ; in the interval between this 
state and the last, the primine has grown over the secundine and nucleus ; the 
apex of the latter has turned com.pletely to the base of the ovulum ; and the 
foramen is contracted into the little perforation at a. 
Fig. 22. Ovulum of Euphorbia lathyris, in a very young state, long before the 
expansion of the flower ; a, kind of cap projecting from the wall of the ovarium 
and into which the apex of the nucleus b is inserted ; this hood finally closes 
over the foramen, into which it protrudes as the nucleus retreats ; c, the 
primine ; the secundine is a similar cap included within the primine. 
Fig. 23. Very young ovulum of Ruta graveolens ; a, the primine ; b, the se- 
cundine ; c, the nucleus : in the end the primine extends, contracts at 
its foramen, and closes over the secundine and nucleus. 
Fig. 24. Vertical section of an ovulum of Alnus glutinosa ; a, the umbilical 
cord ; 6, foramen ; c, primine (and secundine perhaps united with it) ; </, nu- 
cleus ; e, vessels of the raphe ; f, place of the chalaza. 
Fig. 25. An oblique vertical section of the fertilised ovulum of Tulipa ges- 
neriana; a, foramen of the primine (or Exostome) ; 6, foramen of the 
secundine (or Endostome) ; c, primine ; d, secundine ; e, nucleus, its apex 
concealed within that of the secundine ; f, vessels of the raphe ; g, place of 
the chalaza. 
Fig. 2G. Ovulum of Lepidium ruderale ; after A. Brongniart : a, umbilical 
cord ; 6, foramen ; c, point of the nucleus seen through the primine and 
secundine. 
Fig. 27. Half-ripe seed of the same, cut through perpendicularly ; after Bron- 
gniart ; a, the umbilical cord ; b, foramen ; c, primine ; d, secundine ; e, nu- 
cleus ; /, embryo partially formed, its radicle pointing to the foramen ; g, the 
point where the nourishing vessels of the placenta expand (the chalaza). 
Fig. 28. A perpendicular section of the ripe seed of the same, after A. Bron- 
gniart ; the primine and secundine are consolidated ; and the nucleus is 
entirely absorbed by the embryo ; a, umbilical cord : b, foramen, now become 
the micropyle ; g, chalaza; /^, cotyledons of the embryo; i, radicle; ky 
plumula. 
Fig. 29. Mode of fertilisation in Cucurbita Pepo, after Adolphe Brongniart ; 
a, a portion of the placenta ; 6, ovulum ; c, its foramen ; d, the bundle of stig- 
