Related Words

Gametophyte: The haploid stage of a plant exhibiting alternation of generations, generates gametes by the process of mitosis.

Microgametophyte: Stage of the plant life cycle that develops from or within a microspore. The microgametophyte produces sperm in specialized structures known as antheridia.

Ovule: In seed plants, a protective structure in which the female gametophyte develops, fertilization occurs, and seeds develop; contained within the ovary. Structures inside the ovary of the flowe . . . View Full Definition

Ovaries: 1) In animals, the female gonads, which produce eggs (ova) and female sex hormones. 2) In fiowers, part of the female reproductive structure in the carpel; contain the ovules, where egg deve . . . View Full Definition

Pollen Grains: The containers for male gametophytes of seed plants produced in a microsporangium by meiosis. Microspores produced by seed plants that contain the male gametophyte.

Prothallus: In ferns, a small heart-shaped bisexual gametophyte.

Tube Nucleus: One of the cells in the male gametophyte in seed plants. The tube nucleus grows through the stigma, style, and into the ovule, clearing the way for the sperm nuclei to enter the embryo sac.

Seed: Structure produced by some plants in which the next generation sporophyte is surrounded by gametophyte nutritive tissues. An immature sporophyte in an arrested state of development, surround . . . View Full Definition

Nonvascular Plants: Plants lacking lignified vascular tissue (xylem), vascularized leaves, and having a free-living, photosynthetic gametophyte stage that dominates the life cycle. Common examples are the mosse . . . View Full Definition

Microspores: Four haploid cells produced by the meiotic division in the pollen sacs of fiowers or microsporangia of gymnosperms. Microspores undergo mitotic division and become encased in a thick protect . . . View Full Definition