The anther is an enlarged, terminal portion of the stamens in which pollen is produced, which is usually divided into two loculi. The term antèra comes from the Greek antheros, which means flowery.
Each anther is made up of two symmetrical parts, which are the cases, joined by a parenchymal (connective) tissue in which a vascular bundle runs. Each case, in the young anther, contains two cavities (loggias or loculi) that merge just before the dehiscence, that is the opening, of the anther. The loggias contain the granules of pollen, and are covered with a fabric, the carpet, which nourishes the pollen grains during their development and participates in the formation of their cell wall. Below the epidermis is a layer of thick cells, with a thickened wall, the endothelium; they are responsible for the dehiscence of the anther: which occurs as a result of the dehydration of the anther.
Based on the point of insertion of the anthers on the filament, the anthers are defined by various names:
– basifisse, if inserted for the base on the filament;
– dorsifisse, if inserted for the back;
– apicifisse if inserted for the apex;
– ventrifisse, if inserted for the ventral part.
Furthermore, depending on how the opening takes place, they can be: apical, transversal or longitudinal.
Looking transversely at a section of a young anther, the following layers can be identified from the outside to the inside:
– Epidermis (or esotecio), thin and continuous. Sometimes it can break or self-collapse or stop;
– Mechanical fabric (or endothelium): fibrous layer above the outer edges of the pollen bags. Sometimes it continues in the connective;
– 2 – 4 parietal layers of parenchymatous cells, which soon disappear crushed, or degenerate rapidly;
– Mat or nutritive tissue;
– Dirty tissue (or archesporio): it constitutes every pollen sac. The cells of the sporogenous tissue form mitotic divisions of the mother cells of the pollen or microsporocytes, quite large cells with a voluminous nucleus.