User:Jweave23/Gymnocarpium dryopteris

Lead
It is a seedless, vascular plant (with xylem and phloem) that reproduces via spores (not seeds or flowers) and have a life cycle with alternating, free-living sporophyte and gametophyte phases.



Lifecycle
Like most plant species, oak fern alternates generations, where there is a diploid generation in the form of a sporophyte (which produces spores), and is followed by a haploid generation in the form of a gametophyte (which produces gametes). The sporangia are found in clusters on the underside of the leaf, called sori. Each sporangium produces multiple sporocytes, with each sporocyte dividing twice, giving rise to four non-sexual spores. Once the spores germinate, they form a prothallus, which develops a number of archegonia (ovaries), and antheridia (spermaries). If water is present, the spermatazoids travel from the antheridia to the archegonia and the egg is fertilized when the two come into contact. An embryo then grows out of the gametophyte, producing a sporophyte.

Description[edit]
Gymnocarpium dryopteris has small, delicate fronds up to 40 cm (16 inches) long, with ternately-compound pinnae (leaves). Fronds occur singly. Each petiole grows from one node on a creeping rhizome. On the underside of matured pinnae the naked sori can be found (the Latin generic name gymnocarpium means "with naked fruit"). The species grows in coniferous woodlands and on shale talus slopes.

Gymnocarpium dryopteris, a forest understory plant, is not found in association with Quercus (oak).

In cultivation in the UK this plant and the cultivar "Plumosum" have gained the Royal Horticultural Society’s Award of Garden Merit.

Habitat
Oak ferns commonly occur in moist, shady forests, where with wet soil and humid conditions. Often found in drainage areas, ditches and North-facing slopes. Oak fern thrive in soils that are well-drained and have a ph of 4.5-6.4. Soil texture varies from silty, clay loams, to sandy gravel. Oak fern occurs at elevations of 1,700-4500 feet along moderately steep slopes with north, east and west aspects.