Morjphology of the Female Flower of Gnetum, 
81 
The results of these various attempts to find evidence for the foliar 
insertion of the Grnetalean ovule rather tend to confirm the opinion of those 
who have adopted the simplest interpretation of the observed facts and have 
accepted the ovule as truly cauline in position. In any case neither of the 
hypotheses (1) that the inner ovular envelope is an ovary ; (2) that the 
ovule is foliar in position now or in ancestral types, can be used to support 
the other. Each of them lacks the evidence necessary to establish it. 
In attempting to interpret doubtful structures occurring in the group 
Gnetales we encounter special difiiculties which we are perhaps a little 
inclined to under-estimate. Of the origin of the group we know nothing. 
We have good reason to believe that the three existing genera are the 
remnants of an ancient race once more numerously represented than it is 
now ; even this is open to question, as MM. Lignier and Tison have shown. 
Their relations to the rest of the Gymnosperms, as to the Angiosperms, are 
quite obscure; those obtaining between the still living members of the 
group are but little clearer. While we need not yet despair of finding 
evidence sufiicient to illuminate some, perhaps all, of these obscurities, it 
cannot be denied that, at the moment, no clear light has been thrown upon 
any of them. 
In the meantime the value of interpretations founded upon analogy with 
other Gymnosperms, extinct or living, or with the Angiosperms, unless they 
are adequately supported by internal evidence, is the value of the new lines 
of investigation which they indicate. Internal evidence has convinced the 
great majority of those who have studied members of the group that in 
spite of the appearance in them of certain Augios23erm characters, they are 
essentially Gymnosperms. The important investigation of the floral 
structure of Welwitschia which we owe to MM. Lignier and Tison does not 
appear to unsettle the conclusions* reached by Eichler in 1863 — " Gnetaceae 
vere sunt Gymnospermae. . . . Ilia est gravissima ovulorum dignitas 
morphologica, quod hand, ut Cycadeis, e carpophyllo enata qualitatem 
teneant foliaceam, sed axis floralis ipsius summitatem sistant." 
If these considerations are allowed to have weight, our knowledge of the 
morphology of the female flower of Gnetum as extended by MM. Lignier 
and Tison's latest investigation f may perhaps be summarised as follows : 
(1) The two outer envelopes of the complete, the single outer envelope 
of the incomplete, female flower are homologous with the cupule of the 
spike. Here, as in the Angiosperms, sterile reduced leaves exercise a pro- 
tective function with regard to the megasporangium. This resemblance 
* It should, however, be stated hero that Professor Lignier , in the letter referred 
to (p. 8), says: "En ce qui concerne Tinterpretation ovaire au lieu de t^gfument 
ovulaire, nous avons trouve de nouveaux arguments (in Ephedra) tres differents de 
ceux offerts par le Welwitschia et qui nous semblent beaucoup plus probants." 
t Lignier and Tison, 1913. 
6 
