252 



THE FLOWER. 



extending from top to bottom (Fig. 493), the suture or line of 

 dehiscence. Commonly this line is lateral or marginal : not 

 rarely it faces forward or backward. In the vast genus Solanum, 



to which the Potato belongs, in most Ericaceous plants (Fig. 

 458, 494), in Polygala, and in many other flowers, the anther- 

 cells open only by a hole (foramen or pore} , or at most a short 

 chink, at the tip, through which the pollen has in 

 some way to be discharged. In Vaccinium (Cran- 

 berry, Blueberry, &c.), the pore-bearing tip of the 

 anther-cell is prolonged considerably, often into a 

 slender tube, as in Fig. 340. In the Barberry (Fig. 

 495) and in most of that family, also in Lauraceas, 

 the whole face of each anther-cell separates by a con- 

 tinuous line, forming a kind of door, which is attached at the top, 

 and turns back, as if on a hinge : in this case, the anthers are said 

 to open by uplifted valves. In the Sassafras and many other 

 plants of the Laurel family, each lobe of the anther opens b}- two 

 smaller valves of the kind, like trap-doors. 



461. The attachment of the anther to the filament presents 

 three principal modes, which are connected b^' gradations. 

 These are the 



Innate (Fig. 495, 496), in which the anther directly continues 

 and corresponds to the apex of the filament, the cells usually 

 dehiscent strictly marginal!}', the lobes or cells not looking or 

 projecting either inward or outward. 



FIG. 493. A stamen, with its anther, 6, surmounting the filament, a, and opening 

 in the normal manner down the whole length of the outer side of each cell. 



FIG. 494. Stamen of a Pyrola ; each cell of the anther opening by a terminal ori- 

 fice or pore. 



FIG. 495. Stamen of a Barberry ; the cells of the anther opening each by an up- 

 lifted valve. 



FIG. 496. A stamen of Isopyrum biternatum. with innate anther. 497. Stamen of 

 Liriodendron, or Tulip-tree, with adnnte extrorse anther. 498. Stamen of OSnothera 

 glanca, with the anther fixed by its middle and versatile 



FIG. 499. A stamen of Asarum Canadense, with adriate anther and prolonged tip 

 to connective. 



