LESSON 17.] THEIR STRUCTURE AND PARTS. 



113 



the filament may be of any shape ; but it is commonly thread-like, 

 as in Fig. 231, 234, &c. 



291. The Anther is the essential part of the stamen. 

 It is a sort of case, filled with a fine powder, called 

 Pollen, which serves to fertilize the pistil, so that it 

 may perfect seeds. The anther may be considered, 

 first, as to 



292. Its Attachment to the filament. Of this there are 

 three ways ; namely, the anther is 



Innate (as in Fig. 232), when it is attached by its base to the 

 very apex of the filament, turning neither inwards nor outwards ; or 



Adnate (as in Fig. 233), when at- 

 tached by one face, usually for its 

 whole length, to the side of the fila- 

 ment ; and 



Versatile (as in Fig. 234), when fixed 

 by its middle only to the very point of 

 the filament, so as to swing loosely, as 

 we see it in the Lily, in Grasses, &c. 



293. In both the last-named cases, 

 232 233 234 the anther either looks inwards or out- 



wards. When it is turned inwards, or is fixed to that side of the 

 filament which looks towards the pistil or centre of the flower, the 

 anther is incumbent or introrse, as in Magnolia and the Water-Lily. 

 When turned outwards, or fixed to the outer side of the filament, it is 

 extrorse, as in the Tulip-tree. 



294. Its Structure, &c. There are few cases in which the stamen 

 ,rs any resemblance to a 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 answer- 

 ing 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. It is very con- 

 spicuous in Fig. 23*2, where the connective is so broad that it separates 

 e two cells of the anther to some distance from each other. 



FIG. 231. A stamen : a, filament ; b, anther discharging pollen. 



FIG. 232. Stamen of Isopyrum, with innate anther. 233. Of Tulip-tree, with adnate (and 

 extrorse) anther. 234. Of Evening Primrose, with versatile anther. 

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