Sterile plants produce microspores aborted in tetrads, no visible pollen shed, and parthenocarpic pods bearing no seeds. |
The megaspores are, of course, very much larger than the microspores. |
The number of microspores produced is very large, but only four megaspores are borne in each megasporangium. |
In the Scotch pine the microspores are ripe about the end of May. |
In the male cones, microspores are produced from microsporocytes by meiosis. |
They have male spores called microspores and female spores called megaspores. |