1-28 PROF. OLIVER ON THE STRUCTURE OF THE ANTHER. 
leaf, and to the development of the lobes in some cases upon the under rather than the 
upper surface, I am not prepared at present to enter upon any discussion. It seems 
probable that, in these respects, there may be many modifications of the prevailing 
structure. 
The circumstance that the anterior pollen-cells of anthers are generally slightly lower 
than the posterior ones*, and that anthers are so commonly intr or se, conforms entirely 
to the view that anther-cells morphologically correspond to thickenings of the paren- 
chyma of the metamorphosed leaf in a manner essentially the same as we find indicated 
in the abnormal Geranmm. In reference to the margin of the staminal leaf, I ought to 
observe that, when I have been able satisfactorily to trace it down the outer thickened 
portion of the lamina in the Geranium, I have found it to lose itself on the rounded outer 
surface of the exterior pollen-lobes, and not to become in any way coincident with the 
sutures ; but this observation I have been unable to repeat easily, from the withered 
4ate of the specimens which were left me to examine in September. There has appeared 
to be some frequent, if not constant, connection between the inner or lower anther-lobes 
of the abnormal stamens and the lateral veins of the lamina, as is the case, I believe, 
with the thickened lobes at the base of the petals in the Barberry ; but upon the relation 
of the anther-cells to the vascular bundles of the stamens, I have nothing to suggest. 
* In some plants, e. g. y Loranthus europceus, the anterior cells are remarkably lower than the posterior. In this 
species the line of dehiscence is, in part, along the junction of the anterior and posterior lobes, in part continued 
above the former, along the inner face of the connective {vide fig. 17, a to b). 
EXPLANATION OE PLATE XLIV. 
Figs. 1 to 8. Petaioid stamens, with marginal thickenings only. 
F\ l to 13. Various stages intermediate between the above and nearly perfect stamens. In fig. 4 but 
one inner lobe is formed. 
Figs. 14 to 16. Transverse sections of anthers similar to those of figs. 11-13. 
Fig, 17. Anther of Loranthus europceus, front view. 
Fig. 18. Anther of Smilax, with cross sections of same. 
