Plants > Seed Plants > Angiosperm Reproduction
I'll use Lilium, a lily, as an example for angiosperm reproduction. Lily flowers, like many other flowers, contain both male and female reproductive parts. Lilies are monocots; like other monocots, they have flower parts in multiples of three: six stamens and an ovary divided into three compartments.
Each anther is divided into four compartments. The anther is part of the sporophyte; it is diploid.
Meiosis occurs inside the anther, producing haploid spores (not shown in this picture).
After meiosis, each spore divides mitotically, eventually producing a single cell with two or three haploid nuclei. This multinucleate cell is the male gametophyte. The male gametophyte gains a tough outer wall to become a pollen grain.
The small spores that form pollen are called microspores; the larger spores
that form female gametophytes in the ovary are called megaspores.
This image of dividing pollen is a magnified detail of the image above. It shows some pollen cells in the process of mitosis. These cells are labeled "anaphase," which is a specific phase of mitosis. (You don't need to remember this term now; the mechanisms of mitosis will be covered in detail in Bio 6B).
The red stringy structures in the anaphase cells are individual condensed
chromosomes. The chromosomes will eventually decondense, forming a single
blob for each nucleus.
If a pollen grain lands on the stigma of another flower, it is likely
to germinate. During germination the pollen grain forms a long pollen
tube that may eventually carry two pollen nuclei into the ovary to fertilize
This page updated September 17, 2011