Open main menu

ANTHER (Gr. ἀνθηρός, flowery), the male organ of the flower. Considered morphologically, it is a modified leaf, the petiole or stem of the leaf becoming the filament of the stamen, and the leaf blade by the separation of its two surfaces forming two thecæ or lodges containing pollen, the midrib of the leaf becoming the connective of the anther. The filament may be absent, when the anther is said to be sessile; and it may be inserted on the style, as in orchids (in the Linnæan class gynandria), or on the corolla. Several filaments may be more or less united, sometimes forming a tube around the style, as in malvaceæ (class monadelphia); sometimes a split tube with a single detached filament, as in leguminosæ (class diadelphia); sometimes the tube is split into several portions, forming clusters of stamens (class polyadelphia). The filaments may differ in length in the same flower, as two short and two long (class didynamia), or two long and four short (class tetradynamia). The number of stamens characterizes 13 classes of the Linnæan system, which is now wholly abandoned by botanists. The attachment of the anther to the filament varies. Sometimes the connective is only a prolongation of the filament (adnate anther), which may extend far beyond the anther, as in the oleander. If the filament joins the connective at its centre, it may balance the anther if the connective is linear, in which case the anther is said to be versatile; or if the connective is shield-like, bearing several pollen lodges on its lower edge, it is called peltate. Lilies present an example of the first, and in tulips the connective has a funnel-like hollow in which the filament is fixed; and the juniper, cypress, &c., show the peltate form. The anther appears in the flower bud before its filament as a gland-like excrescence. The two cells on either side the connective often subdivide into four; but as the development progresses the septum disappears and the anther becomes bilocular, or even, by the removal of the connective, unilocular. The lodges are cylindrical, globose, ellipsoid, cordate, kidney-shaped or hastate, or even, as in the squash, undulating or twisted. The surface may be smooth, or downy, fringed, and bearded, as in lobelias. Anthers may be united in the same way as the filaments, as in compositæ (class syngenesia), or they may be suppressed or abortive on some of the filaments. From their position on the connective, they are said to be introrse when the lodges face the style, or extrorse when they are directed outward, which is the more common position. When the pollen is ripe the anther opens, either by pores at the base or apex (and these pores are sometimes at the end two tubular extensions of the lodges), as in the potato and melastoma; or by valves, as in the barberry; or, what is most common, by clefts or sutures on the edge corresponding to the edge of the typical leaf. After the discharge of the pollen the anther collapses, and, if of a yellow or orange color when full, becomes a dark orange-brown.