AT the conclusion of the meiotic divisions in the angiosperm anther, the cytoplasm of each mother cell is partitioned more or less equally between the four daughter spores, which then become isolated from each other by the formation of the callose tetrad wall. As a possible determinant of the pattern of gene expression in the gametophyte, the state of the meiocyte cytoplasm at the time of cleavage is of some significance. Is the cytoplasm bequeathed simply a sample of that of the original diploid archesporial cell, or does some metamorphosis occur concurrently with meiosis ? An answer to this question could cast light on the control of the sporophyte–gametophyte alternation, and be relevant also to the problem of cytoplasmic inheritance.