DEVELOPMENT OF THE ANTHER 47 



Following up this idea of the typical unity of the several 

 floral appendages, Morphologists have endeavoured to recognize 

 in the stamen parts corresponding respectively to portions of the 

 petal : — Thus the filament is taken as the homologue of the 

 claw or petiole, the anther is supposed to represent the blade, 

 the cavities being formed by an involution of the same, and the 

 line of dehiscence a suture made by the connivence of the mar- 

 gins. And it may be admitted that this homology is supported 

 by the appearance of a section of a mature anther (see Diagram 

 IV) and further, by analogy with the ovary in which the inflexion 

 of carpellary leaves is often sufficiently obvious. 



But however specious a theory may be, unless it can stand 

 the test of direct observation it is liable to be questioned. The 

 writer of the article on Botany in the present edition of the "Ency- 

 clopaedia Britannica " says " The homologies of the stamen are 

 not yet satisfactorily made out." And if any one will take the 

 trouble to examine an anther in its initial stage he will see that 

 there is no appearance of a leaf-blade (see Fig. V). What he 

 will see is an oval body having a dark line in the centre, and on 

 either side a slight protuberance rendering the central part 

 somewhat concave. A section under the microscope reveals the 

 dark line to be a bundle of fibrous- vascular tissue, and the 

 swollen spaces to be caused by the already commencing formation 

 of pollen. Another section of a more advanced anther will 

 exhibit a septum separating each lobe into two loculi, thus con- 

 stituting the ordinary quadrilocular anther. This partition wall 

 appears to me analogous to the well-known septum seen in the 

 ovaries of the Cruciferee. In the case of the bilocular anther, 

 characteristic of some species, it is believed that the septum has 

 been absorbed, but may it not also have been aborted ? 



The dehiscence of the anther is easily accounted for on the 

 hypothesis of the follicles being formed by connivent leaf mar- 

 gins, as then the cohesion of parts would be but slight and 

 easily sundered — but, rejecting that plan of making the follicles 

 there are two ways of explaining the openings ; we may suppose 

 the longitudinal slit to be caused by absorption or by the walls 

 being ruptured by the swelling pollen along the line of greatest 

 tension and least resistance. I have not yet been able to arrive 

 at a conclusion on the subject. 



