EMBRYOLOGY OF THE AMENTIFERJE. 421 
inheritance. Whether the esca were originally acquired to assist the embryo-sac to 
come in contact with the pollen-tube or for foraging purposes is immaterial from the 
present point of view. Physiological considerations in no way detraet from the classi- 
ficatory value of these ceca. 
5. The presence of tracheides around the base of the embryo-sae in Castunea is a 
curious and unexpected link between the Cupuliferze and Casuarina. Alone this feature 
might be regarded as too detached and fragmentary to be of any value as a point of 
agreement, but when we remember that we can suggest no function subserved by them 
either in Casuarina or in Castanea, and that their appearance is inconstant in both 
cases, the probability is increased that they represent some former organ * possessed by 
the common ancestor of Casuarina and. the Сара Шеге, It might be noted here that 
although the ovules of our British chalazogamic Amentiferee possess but one integument, 
Casuarina, in common with the Cupuliferze, possesses a second. 
Conclusion.—There is still a large part of my work to be done. I have not yet 
relinquished all hope that the Amentiferæ are a field of research in which we may find 
some clue to the solution of the vexed problem of the homology of the antipodals and of 
the fusion of the polar nuclei of the embryo-sae, and it will be partly with this object in 
view that I continue and extend my investigations. 
DESCRIPTION OF THE PLATES. 
Рглте LXVII. 
Fagus. 
Fig. 1. A longitudinal median section of young ovule of date May 4, 1892. ep., the beginning of the 
apical divisions of the epidermis above the archesporium ; @., archesporium mother-cells ; 
i., integument forming partly at the expense of the epidermis. 
Fig. 2. A similar section to the above. This figure shows, when contrasted with the previous, the early 
laying-down of the anatropy of theovule. The funicle of fig. 1 lies to the right of the figure, 
that of fig. 2 to the left. 
Fig. 3. The same a little later. ep., the beginning of the epidermal сар; a.c., the lowermost cell of the 
leoli are very frequently found in 
most strongly differentiated axial strand. Тһе two nuc 
central cells at this stage. ; 
Fig. 4. Тһе same at a still later date, Мау 10,1892. The epidermal сар is here five cells deep. 
e May 14. The central strand was more clearly 
Fig. 5. A median longitudinal section of nucellus of dat 
marked out than the lateral ones and showed a pointed base. (Semi-diagrammatic.) 
Fig. 6. Ditto, but lateral strands appear of equivalent value. (Semi-diagrammatic.) —— 
Fig. 7. Ditto, gathered May 21. ер» epidermal cap now ten cells деер; e.s., first division of nucleus 
of embryo-sac. 
Fig. 8. Ditto, gathered May 18. ер., as before; t., tapetum ; l. 
nd connecting the chalaza with the sporogenous tissue. 
c., long cell equivalent to three of the 
* Possibly a vascular stra 
