seed fern

seed fern
any of various plants of the order Lyginopteridales (or Cycadofilicales), known only as fossils, having fernlike leaves and reproducing by means of seeds. Also called pteridosperm.
[1925-30]

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▪ plant
      loose confederation of seed plants (plant) from the Carboniferous (Carboniferous Period) and Permian periods (Permian Period) (about 360 to 250 million years ago). Some, such as Medullosa, grew as upright, unbranched woody trunks topped with a crown of large fernlike (fern) fronds; others, such as Callistophyton, were woody vines. All had fernlike foliage; however, they reproduced by seeds (seed and fruit), with ovules (ovule) and pollen organs attached to the fronds. gamete-producing structures in the seeds were surrounded by a hard inner integument and a fleshy outer layer. These features have led some authorities to speculate that these seeds may have been dispersed by animals. Some seeds were large. (Pachytesta gigantea, a seed of Medullosa, grew up to 7 cm [2.7 inches] long.) Pollen organs of seed ferns were also large and complex and were commonly made up of many pollen sacs fused into a large structure. Some authorities suggest that these large structures and the large pollen grains they contained were evidence of pollination by animals.

Nan Crystal Arens
 

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Universalium. 2010.

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Look at other dictionaries:

  • seed fern — seed′ fern n. pal any of various fossil plants of the order Lyginopteridales (or Cycadofilicales) that had fernlike leaves and reproduced by means of seeds Also called pteridosperm • Etymology: 1925–30 …   From formal English to slang

  • seed fern — n. any of an extinct class (Pteridospermae) of Paleozoic, fernlike cycads that bore naked seeds upon their leaves …   English World dictionary

  • seed fern — noun an extinct seed producing fernlike plant of the order Cycadofilicales (or group Pteridospermae) • Syn: ↑pteridosperm • Hypernyms: ↑gymnosperm * * * noun : a plant or fossil of the order Cycadofilicales : pteridosperm * * * any of various… …   Useful english dictionary

  • seed fern — noun A plant of the ancient order Cycadofilicales, which had fronds like a fern and naked seeds See Also: seedcake, seedcase, seed coat, seedeater, seeder, seedful, seed leaf, seedling …   Wiktionary

  • seed fern — noun Date: 1927 any of an order (Pteridospermales) of extinct cycadophytes with foliage like that of ferns and with naked seeds …   New Collegiate Dictionary

  • seed fern — noun another term for pteridosperm …   English new terms dictionary

  • 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 seed — noun The asexual, dustlike spores of a fern which resemble seeds Superstition held fern seed renders one invisible See Also: seedcake, seedcase, seed coat, seedeater, seeder, seed fern …   Wiktionary

  • seed stock — noun a) A stock of seed The estates present seed stock comprises seedlings, bulbs and various nuts b) Any supply for planting in general Sustainable hunting and fishing cares as much for its seed stock as for catch or haul See Also: seedcake …   Wiktionary

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