SECTION 9.] 



ANTHERS. 



101 



> 



I 



Tetrad t/namous, when, being only six, four of them surpass the other 

 two, as in the Mustard-flower audall the Cruciferous family, Fig. 235. 



286. The Filament is a kind of stalk to the anther, commonly slender 

 or thread-like : it is to the anther nearly what the petiole is to the blade of 

 a leaf. Therefore it is not an essential part. As a leaf may be without 

 a stalk, so the anther may be Sessile, or without a filament. 



287. The Anther is the essential part of the stamen. It is a sort of 

 case, filled with a fine powder, the Pollen, which serves to fertilize the pis- 

 til, so that it may perfect seeds. The anther is said to be 



Innate (as in Fig. 292), when it is attached by its base to the very apex 

 of the filament, turning neither inward nor outward ; 



Adnate (as in Fig. 293), when attached 

 as it were by one face, usually for its whole 

 length, to the side of a continuation of the 

 filament; and 



Versatile (as in Fig. 294), when fixed' by 

 or near its middle only to the very point of 

 the filament, so as to swing loosely, as in 

 the Lily, in Grasses, etc. Versatile or ad- 

 nate anthers are 



Introrse, or Incumbent, when facing in- 

 ward, that is, toward the centre of the flow- 

 er, as in Magnolia, Water-Lily, etc. 



Extrorse, when facing outwardly, as in the Tulip-tree. 



288. Rarely does a stamen bear any resemblance to a leaf, 

 or even to a petal or flower-leaf. Nevertheless, the botanist's 

 idea of a stamen is that it answers to a leaf developed in a 

 peculiar form and for a special purpose. In the filament he 

 sees the stalk of the leaf; in the anther, the blade. The 

 blade of a leaf consists of two similar sides ; so the anther 

 consists of two LOBES or CELLS, one answering to the left, the 

 other to the right, side of the blade. The two lobes are often 

 connected by a prolongation of the filament, which answers 

 to the midrib of a leaf ; this is called the CONNECTIVE. This 

 is conspicuous in Fig. 292, where the connective is so broad 

 that it separates the two cells of the anther to some distance. 



289. A simple conception of the morphological relation of 

 an anther to a leaf is given in Fig. 295, an ideal figure, the lower part rep- 

 resenting a stamen with the top of its anther cut away ; the upper, the 

 corresponding upper part of a leaf. 



FIG. 292. Stamen of Isopyrum, with innate anther. 293. Of Tulip-tree, with 

 adnate (and extrorse) anther. 294. Of Evening Primrose, with versatile anther. 



FIG. 295. Diagram of the lower part of an anther, cut across above, and the upper 

 part of a leaf, to show how the one answers to the other; the filament to petiole, 

 the connective to midrib; the two cells to the right and left halves of the blade. 



