Hornworts

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A small bryophyte plants belonging to the phylum Anthocerophyta; any of several submerged plants of the genus Ceratophyllum, forming branched masses in quiet water and having finely dissected, whorled leaves and minute unisexual flowers. 

Unlike liverworts but like mosses, hornwort sporophytes have stomata. The hornwort gametophyte consists of a low thallus, out of which numerous slender, upright sporophytes tipped with sporangia grow. The sporophyte has a meristem that elongates the sporophyte with new growth, a feature that distinguishes the plant from the other bryophytes. The name of the hornworts was suggested by the hornlike appearance of the sporophytes.

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