Overview
(Gr. anthos: flower; keras: horn; phyton: plant) A phylum comprising about 100 species of simple nonvascular plants, the hornworts (or horned liverworts), found worldwide in temperate and tropical regions on tree trunks, riverbanks, and other damp locations. They resemble thallose liverworts (see Hepatophyta), but produce long horn-shaped green sporophytes, which split longitudinally to release the spores. Hornwort cells each contain a single chloroplast inside which, uniquely among plants, is a pyrenoid, associated with starch production. Some species have separate male and female plants, while others have both types of sexual organ on the same plant. The motile sperm swim through the surface water film to fertilize the female gametes, and the resultant embryo gives rise to young sporophytes. Young gametophytes arise directly from the germinating spores. Hornworts were formerly classified as a class (Anthocerotae) of the Bryophyta.
Taxonomy
The Phylum Anthocerophyta is further organized into finer groupings including:
- Subphylum (1): Anthocerotae
- Class (1): Anthocerotopsida
- Species: ZipcodeZoo has pages for 68 species, subspecies, varieties, forms, and cultivars in the Phylum Anthocerophyta.
Classes
Anthocerotopsida
Hornworts are a group of bryophytes, or non-vascular plants, comprising the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. The flattened, green plant body of a hornwort is the gametophyte plant. [more]
At least 155 species and subspecies belong to the Class Anthocerotopsida.
More info about the Class Anthocerotopsida may be found here.
Sources
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