Notes, 
945 
the four being, in fact, less deeply sunk below the surface than in an average terminal 
archegonium of the same age, the neck being only a few microns from the mega- 
spore membrane. The megaspore membrane seems to be fairly uniform over the 
whole of the prothallus, instead of being thinner over the apex as is normally the case, 
and is seen to be stretched over the depressions leading to the necks, instead of 
following the cell outlines. 
The question naturally arises whether this lateral position ofarchegonia in Pinas , 
perhaps the most stereotyped of all Conifers in the details of its development, is to be 
regarded as a reversion to an ancient type, a new departure of the nature of a 1 freak ' 
or ‘ mutation ’, or a pathological condition induced by injury. As regards the last 
suggestion, it may be dismissed at once. Collections were only made from properly 
grown and uninjured ovules in healthy-looking cones, and neither before nor after 
sectioning was any trace seen of injury at or near the apex of the prothallus. The 
slight crushing seen in and near the two lower archegonia was almost certainly caused 
in dissecting out the prothallus for fixing. Between the two remaining alternatives it 
is not easy to decide. Most of the workers on the genera of Conifers with normally 
lateral archegonia (including the present writer) have regarded this feature as an 
ancient or ‘ reversionary ’ character, but the evidence is perhaps not very conclusive. 
In the only Cycad with lateral archegonia, the genus in which they occur appears in 
some other respects the most specialized member of the group. 
Of all groups of plants the Conifers are probably the most puzzling in the 
apparent association of both ‘ ancient * and relatively ‘ modern ’ characters in the same 
plant, and it must not be hastily assumed, because lateral archegonia are associated in 
Araucarians with some undoubtedly ancient characters, anatomical and otherwise, 
that they therefore constitute a primitive feature. The discovery of wholly lateral 
archegonia in another tribe of Pinaceae may probably be best regarded in the present 
instance as rather of the nature of a 1 mutation ’ than a ‘reversion if so, it lends support 
to the view that the condition is a modern specialized one. This view certainly does 
not simplify the already rather complicated problem presented by the Araucarians, 
but if applied to the Callitrineae, it brings this character into better agreement with the 
reduced cones and male gametophyte, and other ‘ modern ’ characters which need not 
be further specified. In Sequoia the other evidence is also conflicting and therefore 
does not largely affect the problem one way or the other. 
The view suggested is put forward tentatively, but in any case it seems clear that 
the abnormal prothallus, here described, must be taken into consideration as one link 
in a chain of evidence, not yet completed, which will eventually settle the question of 
the ‘ primitive ’ or ‘ specialized * nature of lateral archegonia in Conifers. Further 
investigation of the Araucarineae on the one hand, and of the Callitrineae on the 
other, is likely to shed considerable light on the problem. 
W. T. SAXTON, M.A., F.L.S. 
Botanical Laboratory, 
South African College, 
Cape Town. 
