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Transactions of the Royal Society of South Africa. 
Actinostrobus the position of the pollen- tube determines which of the 
very numerous archegonial initials become functional archegonia." * It is, 
therefore, clear that nuclei in any part of the prothallus in some Conifers 
may acquire the potentialities of those of archegonium-initials, though these 
potentialities sometimes owe their realisation to conditions not inherent in 
the prothallus. If this is the expression of a tendency which develops as 
the evolution of higher forms proceeds in the Conifers or other archegoniate 
seed-bearing groups, its complete development will convert the prothallus 
into a mass of archegonia, with the elimination of all vegetative tissue. 
That there is adequate evidence of the existence of such a tendency in the 
Coniferae is the opinion of some who have made a study of the group.f 
Coulter and Chamberlain recognise a further tendency " among Pina- 
ceae, and notably among Coniferales in general ... to develop arche- 
gonia earlier and earlier in the ontogeny of the gametophyte, a tendency that 
expresses itself somewhat irregularly but none the less clearly, and that 
reaches its extreme expression in the appearance of archegonial initials 
immediately after the free nuclear stage of the gametophyte." + This con- 
dition is attained, for example, in Torreya, in which " any earlier differentia- 
tion would occur in the stage of the free nuclei and would result in the 
selection of eggs and in the elimination of archegonia." § Cupressus Gove- 
niana is stated by Land,|| on evidence furnished by Juel,^ to have taken " a 
step beyond the archegonium and formed free eggs." Such a case occurring 
among the Conifers would be of particular interest, but Land's statement 
goes beyond Juel's facts. The latter found that cell-formation in the 
embryo-sac failed in nearly all cases studied, but " einmal fand ich ein 
zelliges endosperm mit jungen Archegonienlagen." Fertilisation was not 
observed ; failing this, it is impossible to regard the free nuclei of the sac 
as gametes. The one case in which the formation of vegetative cells and 
archegonial initials was observed rather suggests that the majority of the 
ovules were immature or abnormally developed in the artificial conditions |! 
under which the tree was growing. 
The typical form of archegonium in the gymnosperms is already greatly 
reduced ; reduction carried very little further would eliminate all but the 
essential part of it, the gamete. The neck-canal cell has disappeared and a 
general tendency to eliminate the ventral canal cell is recognised. ft 
There is, therefore, some evidence that these tendencies do exist among 
* Saxton, 1913, p. 327. 
t Coulter, 1909 ; Saxton, 1913 ; Land, 1907. 
X Coulter and Chamberlain,' 1909, p. 263. 
§ Idem, hoc. cit., p. 330. 
II Land, 1909, p. 285. 
% Juel, 1904. 
Juel, 1904, p. 57. 
ft Coulter and Chamberlain, 1910, p. 420. 
