1128 Thoday .— The Female Inflorescence and Ovules of 
probable that there is in this seed a different relation between the integu¬ 
ment and tube. 
That the micropylar tube in Cycadeoidea also, however, corresponds 
with the inner integument in Gnetuni , there seems to me little doubt. 
Wieland says that ‘ the interior layer of the micropylar tube is regarded as 
a continuation of the wall of the nucellus ’; that is to say, that it becomes 
free from the nucellus at a given level, but is fused with it below. It may 
be that in Cycadeoidea the external layers of the micropylar tube were fused 
with the palisaded outer integument, as in the mature ovules of such species 
as G. scandens . The outlines sketched in Wieland’s Fig. 63 (2), p. 122, sug¬ 
gest this. It appears that the palisaded stony layer must have been pro¬ 
longed upwards in this form, clothing the tube. 
Owing to the difficulties in interpreting the material, the account of the 
relations of the nucellus with the micropylar tube and integument in Bennet- 
tites is very confusing. 1 Lignier describes a small cavity, ‘ corpuscular 
mass,’ in the apex of the main body of the nucellus and also, above the main 
body, a large ‘ lysigenous ’ pollen chamber, beyond which the nucellus is 
prolonged upwards as a beak. 1 This beak projects into the micropylar 
tube. Miss Berridge has suggested that Lignier’s ‘ corpuscular mass * is the 
true pollen chamber, agreeing in position with the pollen chamber of Gnetum. 
On the other hand, she regards the ‘ nucellar beak ’ as probably homologous 
with the secondary closing tissue which fills up the micropylar tube in 
Gnetum , and which has here become separated from the tube by an accident 
of preservation ; and she regards the space between the beak and main body 
of the nucellifs, not as a pollen chamber, but as comparable with the large 
space between the micropylar tube (or inner integument) and nucellus in 
Gnetum , which occurs also in Wieland’s Cycadeoidea where no nucellar beak 
is figured. 2 In G. Gnemon the lower part of the micropylar tube below the 
closed portion is lined by a ragged torn layer of cells, and is very suggestive 
of Lignier’s ‘ pollen chamber ’ ; in G. africanum the thin-walled epidermis 
is still intact, but it is easy to see how, if not well preserved, it would become 
torn and ragged. 
1 Wieland does not describe any such complex structure in Cycadeoidea. 
2 Here the micropylar tube is open and the ovule is probably young, so that if the nucellar 
beak corresponds with closing tissue its presence would not be expected. Another point of difference 
between Wieland and Lignier’s account supports Miss Berridge’s theory. Lignier’s Fig. 35, PI. II, 
passes through the base of the so-called ‘ mucron nucellaire ’ and the ‘ pollen chamber’. It is clearly 
surrounded only by the (outer) integument, and there is nothing at this level representing the 
micropylar tube, which, according to him, has fused on to the (outer) integument. But Wieland 
describes the continuity of the inner layers of the micropylar tube and the nucellus. If Wieland’s 
account is true this hollow ‘ beak ’, which is fused below with the nucellus, must represent the base of 
the micropylar tube below the closed portion. It corresponds exactly with Miss Berridge’s figure 
of G. Gnemon at this level, and even its small transverse section, so striking in contrast with 
Figs. 32 and 31 of the upper portion of the micropylar tube, is another suggestive point, since the 
latter sections would pass through the flange and the former would be taken from the lower, narrower 
portion of the tube. 
