hepatica

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Hepatophyta (liverworts) A division of plants, formerly ranked as the class Hepaticae, characterized by a combination of features. The capsule is usually ovoid or spherical and does not have a lid; when ripe, it usually splits into 4 ‘valves’ to release the spores. A tubular perianth often surrounds the developing capsule. The seta is colourless and semi-transparent; it lengthens after the capsule has reached its full size, and is structurally much weaker than a moss seta. Liverworts may be ‘thallose’, i.e. flattened and showing no differentiation into stem and leaves (Anthoceratales, Marchantiales, and Metzgeriales), or ‘leafy’ (Jungermanniales), with leaves normally arranged in 2 or 3 distinct ranks. The leaves never have a thickened nerve or midrib, and are often lobed or segmented. Typically the thallus is attached to a substrate by means of unicellular rhizoids. Liverworts are found in a variety of habitats, particularly in moist conditions.

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Hepatophyta A phylum comprising the liverworts – simple plants that lack vascular tissue and possess rudimentary rootlike organs (rhizoids). Liverworts occur in moist situations (including fresh water) and as epiphytes on other plants. Like the mosses (see Bryophyta), liverworts show marked alternation of generations between haploid gamete-bearing forms (gametophytes) and diploid spore-bearing forms (sporophytes), the latter being dependent on the former for nutrients, etc. The plant body (gametophyte) may be a thallus, growing closely pressed to the ground (thallose liverworts, e.g. Pellia), or it may bear many leaflike lobes (leafy liverworts). It gives rise to leafless stalks bearing capsules (sporophytes). Spores formed in the capsules are released and grow to produce new plants. Liverworts were formerly placed in the class Hepaticae, in the phylum Bryophyta, which now contains only the mosses.