LINNEAN SOCIETY OF LOITDON. XVll 



In position, the integument of the coniferous nucleus appears 

 to me to be similar to that of the ovular envelope of the higher 

 Dicotyledons, close around and on the axis terminated by the nu- 

 cleus, not that of the carpellary leaves, which are on a different axis. 

 Whatever be the theoretical origin of the ovule of the higher Dico- 

 tyledons, on the margin or in the axil of the carpellary leaf, or on a 

 prolongation of the central axis, its funicle, -which bears the integu- 

 ment as well as the nucleus, is a branch, and therefore a secondary 

 axis, and not the main axis of the flower, on which are placed the 

 carpellary leaves. 



In function, the integument in question is purely ovular and 

 seminal, the protection of the nucleus and embryo, not that of the 

 carpellary leaves of the higher Dicotyledons, which bear each a 

 separate stigmatic apparatus for the reception and transmission of 

 the poUen-tubes to the nucleus. This, however, is a purely adaptive 

 character, whose chief value is in respect of practical terminology. 



The result of the above considerations as to the homology of the 

 integument of the nucleus of Conifers as compared with those of the 

 higher Dicotyledons, if I have put them fairly, would therefore be, that 

 genetic homology does not exist, moiphological homology is vague and 

 doubtful, position indicates rather that of the ovular or seminal than 

 of the carpellary integuments, so also does the secondary and adap- 

 tive homology of function. Theoretically, therefore, we should say 

 that the organ in question is not the exact homological representa- 

 tive of either the carpellarj' or the seminal integument ; but prac- 

 tically it is most useful and instructive to treat it as seminal. And 

 as to the name of the two great subclasses of Dicotyledons, as all 

 are agreed that they are essentially distinct, in that the one is de- 

 prived of one of the two envelopes (carpellary and seminal) which 

 exist in the other, the received names Gymnosperms and Angio- 

 sperms appear to be really appropriate, as denoting a fact admitted 

 by both sides, though differently interpreted ; whilst the proposed 

 names Archisperms and Metasperms are founded on a theory 

 which, under the above views, we cannot but quahfy as purely 

 imaginary. 



A valuable portion of Strasburger's essay consists in his detailed 

 illustration of the development of the flowers of Welwitschia, an 

 important contribution to the completion of that history of this 

 plant so thoroughly worked out by Dr. Hooker, so far as the 

 materials at his disposal admitted, in his now celebrated paper in 

 the twenty-fourth volume of our Transactions. Hooker had then 



