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. [Illustration: 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.] 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 representing a stamen with the top of its anther cut away; the upper, the corresponding upper part of a leaf. 290. So anthers are generally _two-celled_. But as the pollen begins to form in two parts of each cell (the anterior and the posterior), sometimes these two strata are not confluent, and the anther even at maturity may be _four-celled_, as in Moonseed (Fig. 296); or rather, in that case (the word _cell_ being used for each lateral half of the organ), it is _two-celled_, but the cells _bilocellate_. [Illustration: Fig. 296. Stamen of Moonseed, with anther cut across; this 4-celled, or rather 4-locellate.] [Illustration: Fig. 297. Stamen of Pentstemon pubescens; the two anther-cells diverging, and almost confluent.] [Illustration: Fig. 298. Stamen of Mallow; the anther supposed to answer to that of Fig. 297, but the cells completely confluent into one.]