248 ORGANOGRAPHY. 



as the anther approaches maturity, the fibrous threads or bands 

 alone remaining in the form of spires, rings, or branched filaments. 

 This layer gradually diminishes in thickness as we approach the 

 suture, and at that line it is altogether wanting. At the suture 

 the exothecium is also commonly thinner than upon the other 

 parts of the lobe. The connective has a structure which in its 

 essential characters usually resembles the filament, i.e. it is 

 composed of a bundle of spiral vessels enclosed in a mass of 

 parenchyma covered by epidermis. Frequently the connective 

 consists of parenchyma only. 



We have already shown that the floral envelopes are homo- 

 logous with leaves, representing them as they do in all their 

 essential chara':ters. We have now to examine the stamen 

 with the view of ascertaining Avhether its parts also have any 

 resemblance to those of the leaf. We have no difficulty in re- 

 cognising the filament as the homologue of the petiole, both 

 from its form, position, and structure, in all of which particulars 

 it is essentially the same. The connective of the anther again, is 

 clearly analogous to the midrib of the leaf, and hence we readily 

 see that the two lobes of the anther correspond to the two halves 

 of the lamina folded upon themselves ; in fact if we take a 

 leaf and fold it in the above manner, and then make a trans- 

 verse section, it will present a great resemblance to the section 

 of the anther already described {fig. 501). We may therefore 

 conclude, that the anther corresponds to the lamina of the leaf, 

 the connective to the midrib, the outer surface to the epidermis 

 of its lower side, and the septa to the epidennis of the two 

 halves of the upper surface of the lamina united and consider- 

 ably thickened. The pollen also corresponds to the general 

 parenchyma situated between the epidermis of the upper and 

 lower surfaces of the leaf. 



Attachment of the Filament to the Anther. — The mode in which 

 the anther is attached to the filament varies in different plants, 

 but it is always constant in the same individual, and hence the 

 characters afforded by such difterences are important in ])ractical 

 botany. There are three modes of attachment which are 

 characterised by special names. 1st. The anther is said to be 

 adnate, when its back is attaclied throughout its whole length to 

 the filament, or its continuation called the connective, as in the 

 Buttercup (Banunculus), Magnolia (fig. 513), Water-Lily 

 (fig. 509), and Barberry ; 2nd, it is innate, Avhcn the filament is 

 only attached to its base and firmly adherent, as in Carcx (fig. 

 488), and Tulip (fig. 510) ; 3rd. it is versatile, wlicn the filament 

 is only attached by a point to the hack of the connective, so 

 that the anther swings upon it, as in Grasses generally (fig. 

 490), in the Lily, in the Evening Primrose, and in the Meadow 

 Saffron. 



