240 ORGANOGRAPHY, 



and 506, cf), which corresponds to the covering of the masses 

 of pollen-forming cells {fig. 498, c/), and is termed the, endo- 

 thccium. This inner lining consists of one or more rows of fibrous 

 cells {fig. 506, cf) ; commonly of that kind called reticulated, 

 but sometimes spiral or annular cells also occur. The membrane 

 forming the walls of these cells usually becomes obliterated as the 

 anther approaches maturity, the fibrous threads or bands alone 

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

 The endothecium gradually diminishes in thickness as we ap- 

 proach the suture, and at this line it is altogether wanting. 

 At the suture the exotheciumis also commonly thinner than upon 

 the other parts of the lobe of the anther. 



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 epi- 

 dermis. Frequently, however, the connective consists of paren- 

 chyma only. 



We have already shown that the floral envelopes are homolo- 

 gous with leaves, representing them as they do in all their essen- 

 tial characters. We have now to examine the stamen with the 

 view of ascertaining whether its parts have in like manner any 

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

 cognising the filament as the horaologue of the petiole, as in its 

 form, position, and structure it is essentially the same. The 

 connective cf the anther again, is clearly analogous to the 

 midrib of the blade, 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 the blade of a leaf and 

 fold it in the above manner, and then make a transverse section, 

 it will present a great resemblance to the section of the anther 

 already described {fig. 499). We may therefore conclude, that 

 the anther corresponds generally 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 epidermis of the two halves of 

 the upper surface of the lamina united and considerably thick- 

 ened. The sutures or lines of dehiscence are commonly regarded 

 as corresponding to the margins of the transformed leaf ; but ac- 

 cording to Oliver, " the sutures of the anther answer to the lines 

 of junction of the outer and inner thickened portions of the 

 lamina on either side of the midrib, and the septa as resulting, 

 in part at least, from the inflected epidermis of the adjacent 

 anther cells." The pollen is commonly regarded as corresponding 

 to the parenchyma situated between the epidermis of the upper 

 and lower surfaces of the lamina 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 frequently 

 throughout entire natural orders, and hence the characters af- 



