This illustration shows the flower and sporophylls of Angiosperms: 1, flower of Sedum with leaf-like perianth, p; microsporophylls, s; megasporophylls, c. 2, microsporophyll of the buttercup, showing four-lobed anther and filament. 3, diagram of a cross-section of anther, showing the breaking down of the tissue about the four sporangia and the beginning of the opening of the anther. 4, one of the sporangia from a young anther, as seen in cross-section-m, spore mother cells. The large cells surrounding the mother cells are nourishing cells, known as the tapetum, and disorganize as the spores mature. At the right a mother cell forming four microspores, the upper one being characterisitic of dicotyledons and the lowr of monocotyledons.