78 
Transactions of the Royal Society of South Africa. 
ness of the open flower. Its form may just as well be an adaptation to 
the despatch as to the receipt of the pollen. In the former we believe^ 
that it plays a not unimportant part ; with the latter we know that it has 
at present no concern, and there is no sufficient reason for supposing that 
it ever has been concerned. If, on the other hand, this stigma-like structure 
had ever in its history played the part of a true stigma, it would be surpris- 
ing that it should have disappeared so entirely from the envelope of the^ 
female flower which does function as a pollen-receiver, and in an exceedingly 
efficient manner. * 
Further, it is well established, in each of the three genera, that the- 
nucellus precedes this envelope in ontogeny. In the female flower of Wel- 
witschia, the megaspore mother-cell is constituted before the first signs of 
the inner envelope are apparent. f The relations are similar in Ephedra and 
Gnetum.:|: In all three the megaspore on germination grows down into the 
axis to a point far ]ielow the level at which the envelope becomes free from 
the nucellus. § || 
These relations are not characteristic of carpels and ovules ; they do 
commonly obtain between integuments and nucelli, more especially among^ 
the Grymnosperms. It is perhaps within the range of possibility that an 
Angiosperm ovary should become so reduced and retarded in development 
as to simulate so remarkably a G-ymnosperm integument, but it seems so- 
improbable that strong evidence would be needed to show that its observed 
characters are so entirely deceptive; and no such evidence is yet forth- 
coming.^ 
If, for instance, it could be shown that the nucellus is not a terminal 
structure but is inserted on the envelope (which in fact arises from it), this 
would go far to reduce the significance of its resemblance to an integument.. 
The question of the cauline or foliar position of the ovule has been much 
discussed, particularly within recent years. If it is truly cauline the difficulty 
of comparing the Grnetalean "flower" with corresponding structures in botk 
the Grymnosperms and the Angiosperms is, in the present state of our- 
. * Pearson, 1909, pi. 23, fig. 11, . T 
t Pearson, 1906, pi. 19, figs. 20, 20 A. ■ ' ■ 
+ Strasburger, 1872, Taf. xv, figs. 45, 46 ; Karsten, 1893, fig. 29. 
§ Thoday and Berridge, 1912, text-fig. 11 ; Thoday, 1911, text-fig. 9; Sykes, 1910^ 
diagr. xviii. 
II Schuster (1911) refuses to regard this envelope as an ovary because of the 
presence of archegonia of the Gymnosperm type. To this Lignier and Tison (1912,, 
p. 171) object that (1) the archegonium is not present in Welwitschia nor in Gnetum ; 
(2) the absence of the archegonium has never been regarded as a necessary character 
of the Angiosperms. These objections are certainly sound ; if the archegonium 
removes Ephedra from the Angiosperms, the absence of archegonia must eqiially- 
remove Welwitschia and Gnetum from the Gymnosperms. 
^ Cf. Church, 1914, p. 122. , - ■ ' ■:; 
