134 



ANATOMY. 



703), after whicli both the septa and the walls of the mother-cells disappear, and the 

 four nuclei (p) which filled them are set free as pollen-grains (fig. 704). As they 

 grow (figs. 706 and 706), the cellular tissue of the anther, in the middle of which the 

 cavities had been formed, are absorbed ; a layer of cells which formed the walls of 

 the cavities now lines the membrane of the epidermis (fig. 699, oe), and rapidly 



changes into a layer of fibrous 

 cells (e) ; the tissue which sepa- 

 rated the small cavities becomes 

 gradually thinner, and forms a 

 septum which projects from the 

 connective towards the line of 

 dehiscence; this septum is soon destroyed, and the two cavities form but one 

 {anther- cell). In some plants this septum is persistent, and the anther remains 

 quadrilocular [Butomus, fig. 326). In many plants the remains of the mother- 

 cells only partially disappear, and the rest connect the pollen-grains, as in 

 Orchis (figs. 359 and 360), where an elastic network causes them to cohere in small 

 masses. 



Carpels. — The anatomy of the carpellary leaves is analogous to that of ordinary 



707. Pear. 

 Very young flower, cut 

 vertically to show the 

 petals, stamens and carpel- 

 lary maramje free on the 

 receptacle (mag.). 



708. Pear. 

 Young carpels, seen from 

 within, at first concave, 

 and the edges afterwards 

 approaching to form 

 the stjle and placentas 

 (mag.). 



703. fear. 

 Yoilng flower, cut vertically 

 to show the growth of the 

 receptacle, the arrangement 

 of the carpels, and the inser- 

 tion of the petals and stamens 

 (mag.). 



711. Pear. 

 Flowei- cut vertically, with the 

 stamens and petals removed, show- 

 ing the carpels enveloped by the 

 receptaculaf cup (mag.). 



leaves ; a cellular tissue (sometimes very succulent, as in berries and drupes), 

 traversed by fibro-vascular bundles, is covered with an epidermis, the outer surface 

 only of which bears stomata ; the bundles ascend from the ovary into the style, 

 occupying its circumference, its centre being hollowed into a canal. 

 The inner walls of this canal, which is formed by the convolution of 

 the uijper end of the carpellary leaf, is covered with projecting cells, 

 and its axis is occupied by soft cellular filaments, named conducting 

 tissue ; it is this tissue which constitutes, on the top or sides of the 

 4ScaiyxTpetai"aS style, the truc stigmatic tissue. The placenta, which transmits 

 ™veT t?™how" t\% nourishment to the seed, and the funicle, which is a prolongation 

 the iSptiiinte cup of the placcuta, consist of a bundle of tracheae surrounded by 

 elongated cells. 

 Inferior ovaries have the carpels encased in a receptacular cup, which is some- 



710. Pear. 

 Young flower, fi'om 



(mag.). 



