194 



ESSENTIAL ORGANS. STAMENS. 



containing a mucilaginous matter (figs. 320, 321). In these cavities 

 cells make their appearance the outer small (figs. 320, 321, c p), 

 forming ultimately the endothecium (fig. 318 c/); the interior layer 

 forming cells in which the pollen is produced (figs. 320, 321, up,). 



As the cavities become larger, the layer of cells (figs. 320, 321, c t), 

 between the endothecium, c p, and exothecium, c e, is gradually 

 absorbed more or less completely, forming at first septa in the cavities : 

 and ultimately the anther assumes its mature form, consisting of two 

 lobes with their membranous coverings (fig. 322, /). 



405. In the young state there are usually four cavities produced, 

 two for each anther-lobe, separated by the connective, and each divided 

 by the septum, which sometimes remains permanently complete, and 

 thus forms a quadrilocular (quatuor, four, and loculus, a pouch or box), 

 or tetrathecal (rlT^us, four, and Sti**, a sac) anther. The four cavities 

 are sometimes placed in apposition, as in Poranthera (fig. 323) and 

 Tetratheca juncea (fig. 324), and at other tunes two are placed above 



Fig. 319. Transverse section of an anther of Cucurbita Pepo, or Gourd, taken from a bud 

 about two millimetres, or l-12th of an English inch, in length. 



Fie 320. Similar horizontal section from a bud in a more advanced state, c e, Outer layer 

 of cellules (Exothecium) forming the epidermis, c t, Intermediate layer of cellules in several 

 layers, most of which are ultimately absorbed, cp, Internal layer of cells (Endothecium), up, 

 Anther-cavities filled with large cells, which constitute the first state of the pollen-utricles. 



Fig. 321. Similar section in a still more advanced state. The letters have the same meaning 

 as in the last figure. 



Fip. 322. Anther of the Almond-tree. ', Seen in front ", Seen behind. //, Filament at- 

 tached to the connective, c, by a point 1 1, Anther-lobes containing pollen. 



