BIOL208 Lecture 15: Non-vascularSeedless Vascular Plants
29 Mar 2018
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Document Summary
Bryophytes represent the earliest lineages to diverge from the common ancestor of land plants. Paraphyletic groups consisting of three phyla of small herbaceous (non- woody), non-vascular plants: The absence of vascular transport systems limits the size of bryophytes. Most tissues only one or a few cells thick. Bryophytes do not form roots, but instead absorb water through their surfaces. Limits bryophytes to habitats where water is abundant. In all three bryophyte phyla, gametophytes are larger and longer living than sporophytes. Bryophytes have free-living haploid gametophytes as the most conspicuous, dominant phase of the life cycle. Smaller diploid sporophytes are present only part of the time, and they are dependent on the gametophyte. A spore germinates into a gametophyte (1n) composed of protonema and gamete-producing gametophore. Mature gametophytes often male or female, and have separate gametangia for eggs and sperm. Female archegonium produces and retains a single egg.
