S topes . — On the Double Natter e of the Cycadean Integiement . 565 
stone layers and outer flesh are one morphologically, and hence to look 
for the plane of fusion of the two integuments either between the inner and 
outer stone layers, or probably as I had originally suggested between the 
stone and the inner flesh. 
The idea that an outer integument might arise as an independent out- 
growth round the ovule in Cycads was suggested by Goebel 1 some time 
ago, who stated that the 4 Wucherungen ’ of Ceratozamia might represent 
the beginning of a second integument. If the Cycads, however, have 
already two integuments these ‘Wucherungen’ may represent a third. 
I have recently examined fresh material of Stangeria schizodon , in which 
there are upgrowths of the sporophyll which are developed to such an 
extent that in some cases they unite to completely enclose and cover 
over the growing ovule, even after it has attained a considerable size. 
‘Wucherungen’ which completely enclose the ovule in this fashion can 
hardly be termed other than ovular coverings, and it seems to suggest the 
possibility of a third integument arising on much the same lines as 
I suppose the second to have done. 
Although Oliver and Scott do not definitely state that they consider 
the cupule of Lagenostoma to be the equivalent of the outer flesh of Cycads, 
yet they suggest (p. 232 loc. cit.) that : ‘The outer (i.e. the cupular cover- 
ing) is probably of later origin, and would appear to have afforded 
protection to the seed only when the latter was quite young. It is quite 
possible that the two enclosures have originated very similarly, i. e. as 
peltate-lobed structures, and that the present integument was once a com- 
paratively unspecialized cupule-like indusium.’ 
If one can consider the inner integument as having once been a ‘com- 
paratively unspecialized cupule-like indusium,’ I can see no reason why 
one cannot suppose the second ‘ cupule-like ’ structure to adhere and form 
the outer integument, nor why the series might not be continued and a 
third added in the same way. There appears to me to be no fundamental 
necessity to limit the integuments to two as Celakovsky has done. 
The outgrowth I observed in Stangeria is entirely free from the outer 
integument of the ovule ; it is undifferentiated in character, and its tissues 
are those of the sporophyll. It is obviously not split off from the outer 
integument, but is the free upgrowth round the already doubly integu- 
mented ovule, and it seems to me to illustrate markedly the case in 
point. 
I have assumed throughout a sporangial theory of the ovule, an 
assumption that seems well justified in the light of recent work on fossils 
and living plants ; the question under discussion is therefore only that of 
the nature of the integuments, and in particular the recognition of the 
double nature of the normal Cycadean integument. 
1 Organographie der Pflanzen, 1898, p. 786. 
