428 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 introrse, 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 Geranium. In reference to the margin of the staminal leaf, I ought to 

 ol)serve that, when I have been able satisfactorily to trace it down the outer thickened 

 portion of the lamina in the Geraniimi, 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 

 state 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., Loranthus europceics, 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 th« connective (vide fig. 17, « to 5). 



EXPLANATION OF PLATE XLIV. 



Figs. 1 to .3. Petaloid stamens, with marginal thickenings only. 



Figs. 4 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 oi Loranthus europmis, front view. 

 Fig. 18. Anther oi Smilax, with cross sections of same. 



