IN CYCADE^ AND CONIFERS. 457 



very different view of the structure of Cycadese and 

 Coniferse, stating, that in their female flowers there is 

 not only a minute cohering perianthium present, but an 

 external additional envelope, to which he has given the 

 name of cupula. 



In 1814 I adopted this view, as far at least as regards 

 the manner of impregnation, and stated some facts in sup- 

 port of it.^ But, on reconsidering the subject in connec- 

 tion with what I had ascertained respecting the vegetable 

 ovulum, I soon after altogether abandoned this opinion, 

 without, however, venturing explicitly to state that now 

 advanced, and which had then suggested itself* 



It is well known that the late M. Richard had prepared 

 a very valuable memoir on these two families of plants ; and 

 he appears, from some observations lately published by his 

 son, M. AchiUe Richard,^ to have formed an opinion respect- 

 ing their structure somewhat different from that of M. 

 Mirbel, whose cupula is, according to him, the perianthium, 

 more or less cohering with the included pistillum. He was 

 probably led to this view on ascertaining, which I had also 

 done, that the common account of the structure of [seo 

 Ephedra was incorrect,* its supposed style being in reality 

 the elongated tubular apex of a membranous envelope, and 

 the included body being evidently analogous to that in other 

 genera of Coniferae. 



To the earliest of the opinions here quoted, that which 

 considers the female flower of Coniferse and Cycadese as a 

 naked pistillum, there are two principal objections. The 

 first of these arises from the perforation of the pistillum, 

 and the exposure of that point of the ovulum where the 

 embryo is formed to the direct action of the pollen ; the 

 second from the too great simplicity of structure of the sup- 

 posed ovulum, which I have shown accords better with that 

 of the nucleus as existing in ordinary cases. 



To the opinions of MM, Richard and Mirbel, the first 



1 Minders^ Voy. ii, 573 {ante, -p. 46). 



2 Tuchey's Congo, p. 454 j^ante, p. 138), et Linn. Sac. Transact, vol. xiii, 

 ^.m{a?ite,p.Z%0,note). 



3 Diet. Class. d'Bist. Nat. torn, iv, p. 395, et torn, v, p. 216. 

 1 Id. torn, vi, p. 208. 



