STRUCTURE.] INNER INTEGUMENT. 29 



to half, and open its whole length ; and that the outer mem- 

 branes (primines) of the two collateral ovules, although 

 originally distinct, finally contract an adhesion by their corre- 

 sponding surfaces, and together constitute the anomalous 

 dissepiment. But it may be reasonably doubted whether the 

 integument here called secundine is not primine, and the 

 supposed primine arillus. In Sir Thomas Mitchell's curious 

 Bottle Tree, (Delabechea) the primine is brittle like an egg- 

 shell, and separates spontaneously from the bony secundine, 

 which eventually cracks the apex of the primine and falls 

 through the hole thus formed. The primines, which are held 

 together by entangled hairs, remain in the follicle long after 

 the secundines and their contents have dropped out. 



The inner membrane (secundine) of the ovule, however, in 

 general appears to be of greater importance as connected with 

 fecundation, than as affording protection to the nucleus at a 

 more advanced period. For in many cases, before impreg- 

 nation, its perforated apex projects beyond the aperture of 

 the testa, and in some plants puts on the appearance of an 

 obtuse, or even dilated, stigma ; while in the ripe seed it is 

 often either entirely obliterated, or exists only as a thin film, 

 which might readily be mistaken for the epidermis of a third 

 membrane, then frequently observable. The apex of the 

 original papilla, which developes itself as nucleus, varies 

 exceedingly in its size in proportion to the entire ovule, if 

 examined in the different families. It often forms a long and 

 nearly cylindrical body, as in Loasa and Pedicularis; in many 

 cases it is shorter, so that that portion of the ovule in which 

 no distinction has taken place between nucleus and integu- 

 ment (the whole being like a fleshy distended stalk) is by far 

 the more predominant, as in all Composites, Canna, Phlox, 

 Polemonium. 



" The third coat (tercine) is formed by the proper mem- 

 brane or skin of the nucleus, from whose substance in the 

 unimpregnated ovule it is never, I believe, separable, and at 

 that period is very rarely visible. In the ripe seed it is dis- 

 tinguishable from the inner membrane only by its apex, 

 which is never perforated, is generally acute and more deeply 

 coloured, or even sphacelated." 



