whisk fern

whisk fern

 either of the two species of the primitive fern genus Psilotum in the family Psilotaceae of the order Psilotales and the class Psilotopsida of the division Pteridophyta (the lower vascular plants (plant)).

      A whisk fern has water- and food-conducting tissues but lacks true leaves and roots. photosynthesis occurs in the aerial stems, and water and mineral absorption occurs in the horizontal underground rootlike stems (rhizomes (rhizome)), which receive water and nutrients from fungi (fungus) through a mycorrhizal (mycorrhiza) association. There are two phases in the life cycle of a whisk fern. The large asexual plants (sporophytes) produce spores that develop into very small colourless sexual plants (gametophytes (gametophyte)), which are similar to rhizomes in overall appearance. Eggs and sperm are produced in special structures on their surfaces. Union of these gametes initiates the second sporophyte phase.

      The genus Psilotum contains two species and one hybrid (P. complanatum, P. nudum, and P. x intermedium) of pantropical plants with whisklike green stems and scalelike appendages called “enations,” which may represent reduced leaves, but they contain no vascular tissue (veins). P. nudum also reaches into the subtropics, growing as far north as the southern United States in the New World, and it is cultivated as a greenhouse plant. In nature, the plants mostly grow as epiphytes (epiphyte) (living on other plants).

George Yatskievych

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Universalium. 2010.

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Look at other dictionaries:

  • whisk fern — noun chiefly tropical clump forming plants of skeletal appearance resembling whisk brooms; lacking roots • Hypernyms: ↑fern ally • Hyponyms: ↑skeleton fork fern, ↑Psilotum nudum • Member Holonyms: ↑Psilotum, ↑genus Psilotum …   Useful english dictionary

  • whisk fern — noun Any of various simple vascular plants, of the family Psilotaceae, that have leafless dichotomous stems and produce spores …   Wiktionary

  • Fern ally — is a general term covering a somewhat diverse group of vascular plants that are not flowering plants and not true ferns. Like ferns, these plants disperse by shedding spores to initiate an alternation of generations. There were originally three… …   Wikipedia

  • fern — fernless, adj. fernlike, adj. /ferrn/, n. any seedless, nonflowering vascular plant of the class Filicinae, of tropical to temperate regions, characterized by true roots produced from a rhizome, triangular fronds that uncoil upward and have a… …   Universalium

  • Fern — /ferrn/, n. a female given name. * * * Any of about 10,000–12,000 species (division Filicophyta) of nonflowering vascular plants that have true roots, stems, and complex leaves and reproduce by spores. Though ferns were once classified with the… …   Universalium

  • fern ally — noun pteridophytes of other classes than Filicopsida • Hypernyms: ↑pteridophyte, ↑nonflowering plant • Hyponyms: ↑whisk fern, ↑horsetail, ↑club moss, ↑club moss, ↑lycopod, ↑ …   Useful english dictionary

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  • Fern — This article is about the group of pteridophyte plants. For other uses, see Fern (disambiguation). Ferns (Pteridophyta) Temporal range: Mid Devonian[1] Recent …   Wikipedia

  • skeleton fork fern — noun pantropical epiphytic or terrestrial whisk fern with usually dull yellow branches and minute leaves; America; Japan; Australia • Syn: ↑Psilotum nudum • Hypernyms: ↑whisk fern …   Useful english dictionary

  • plant — plantable, adj. plantless, adj. plantlike, adj. /plant, plahnt/, n. 1. any member of the kingdom Plantae, comprising multicellular organisms that typically produce their own food from inorganic matter by the process of photosynthesis and that… …   Universalium

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