248 G. Bentham’s Anniversary Address 
as the same purposes came to be answered by more or less per- 
fect unisexuality or other means. 
“Tf then, we are right in concluding that Gnetaces cannot 
have descended from Conifers nor the higher Dicotyledons from 
netacezx, though all may have descended from a common stock, 
we cannot but think that Strasburger has failed in proving any 
genetic homology in their floral envelopes. The question 
returns, therefore, to its old phase, to be determined by morphol- 
ogy, position, and functions. 
“ First, as to morphology. In phsenogamous plants, immedi- 
ately around or among the sexual elements the outgrowths from 
the floral axis are of two kinds, either continuous and uniform 
or oblique all round the axis, or arising in several separate parts: 
. the former are regarded sometimes as mere axial developments, 
sometimes as exceptionally single and one-sided foliar organs ; 
the latter as appendages or leaf-organs, forming part of the 
general phyllotaxy of the plant. To the former class would be 
referred discal excrescences and ovular integuments, to the lat- 
ter carpellary elements. Strasburger shows that the disputed 
envelope in Conifers most frequently, though not always, ap- 
pears at an early stage in the shape of two more or less distinct 
opposite protuberances, that it is consequently foliar, partaking 
of the phyllotaxial system of the plant, not axial nor exception- 
ally monophyllous and unilateral, and that it is therefore carpel- 
lary, not ovular. 
* But here we have another element of uncertainty, which has 
recently been the subject of much controversy, and to which I 
shall presently revert. The limits between axial dilatations and 
regularly formed appendages are not always definite, and occa- 
sionally are wholly obliterated; and the present case may be 
included amongst those in which the distinction is ambigu- 
ous. Morphologically the seminal envelope of Conifers shows 
a tendency to enter into the general phyllotaxial system of the 
lant ; but in several genera it retains the characters of an ax 
tation, or, as Strasburger interprets it,asingle leaf. In @ne- 
tum there is a double inner integument, which he considers en 
tirely ovular or seminal and monophyllous, whilst the outer one 
‘4s, according to his view, carpellary, consisting of two 
organs in conformity with the general phyllotaxy ; but he ad- 
mits (p. 119) that the outer one of the two ovular integuments 18 
traversed by bundles of vessels similar to those of the external 
carpellary envelope, and “only affords a further proof of the 
gS Say ee connection of the two. 
“In position, the integument of the Coniferous nucleus &p- 
— to me to be similar to that of the ovular envelope of the 
igher Dicotyledons, close around and on the axis terminated 
by the nucleus, not that of the carpellary leaves, which are OF 
