Fig. 292. Stamen of Isopyrum, with innate anther. 293. Of Tulip-tree, with adnate (and extrorse) anther. 294. Of Evening Primrose, with versatile anther.
[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 pistil, 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 adnate anthers are
Introrse, or Incumbent, when facing inward, that is, toward the centre of the flower, 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.