The Angiosperms are heterosporous. The stamens of the flower are the male sexual parts and they are highly modified leaves called microsporophylls. The microsporophylls produce anthers or microsporangia.  Within the anther, there are special diploid cells called pollen mother cell or microspore mother cells. The microspore mother cells undergo meiosis to produce haploid microspores or pollen grains. The microspore produces a few celled male gametophytes, each male gametophyte has two cells tube cell and a generative cell. This process is called microsporogenesis.

Gynoecium or pistil is the female sexual parts. The gynoecium is made up of highly modified leaves called megasporophylls or carpels. The megasporophylls fused to form ovaries. The function of carpels is to produce ovules or megasporangia by a process called megasporogenesis. Within the ovules, there are specialized cells called the megaspore mother cells (2n). The megaspores mother cells are diploid (2n) which undergo meiosis or reduction division to form haploid megaspores (n). The megaspores produce a multicellular female gametophyte or embryo sac. The mature embryo sac has a group of three antipodal cells, two synergid cells, one female gamete or egg cell. There are two haploid polar nuclei which fuse together to produce a diploid secondary nucleus.