Vittaria appalachiana

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Vittaria appalachiana
Vittaria appalachiana tuft (cropped).JPG
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Order: Polypodiales
Family: Pteridaceae
Genus: Vittaria
Species:
V. appalachiana
Binomial name
Vittaria appalachiana
Farrar & Mickel

Vittaria appalachiana, or the Appalachian shoestring fern, is a fern species in the subfamily Vittarioideae of the family Pteridaceae. It is native to moist and shaded outcrops in the Appalachian Mountains. It is notable for existing only in the gametophyte stage of development, unlike other fern species in which the sporophyte stage predominates. [1] The species reproduces asexually through gemmae. [2]

Contents

The species was known to bryologists, who at first confused it with a liverwort. Aaron John Sharp brought the species to the attention of pteridologists Warren H. Wagner and Alma Gracey Stokey. It was formally named by Farrar & Mickel in 1991. [3]

Description

The sporophyte (normally the dominant generation of the fern life cycle) is almost never formed in this species. Tiny sporophytes have been found at one site in Ohio, and have twice been produced in culture. The few V. appalachiana sporophytes known have had rhizomes with clathrate (lattice-patterned) scales, and undivided, linear fronds less than 5 millimeters (0.2 in) long, features typical of vittarioid ferns except for their small size. [4]

Most populations of V. appalachiana are composed solely of gametophytes, which take the form of a thin green thallus, which is sparsely to extensively branched. The thallus bears filament-like structures called gemmae which project from its margin near the tips of the branches. The gemmae can fragment from the parent and grow into a new gametophyte. They vary in size from 2 to 12 body cells in length. Rhizoid primordia are present only on the two end cells of the gemmae, and are sometimes lacking from one or both. In general, gemma production is less uniform than in the gametophytes of other species of Vittaria. [4]

Habitat

Vittaria appalachiana grows in dense colonies in dark, moist crevices in non-calcareous rock. Habitats are usually dark and sheltered from extremes of temperature, and humidity; rock shelters and smaller cavities are favored. It occasionally appears as an epiphyte, growing on the bases of trees protected within narrow gorges. Populations have been found at altitudes from 150 to 1,800 meters (490 to 5,900 ft). [4]

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A gametophyte is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the sexual phase in the life cycle of plants and algae. It develops sex organs that produce gametes, haploid sex cells that participate in fertilization to form a diploid zygote which has a double set of chromosomes. Cell division of the zygote results in a new diploid multicellular organism, the second stage in the life cycle known as the sporophyte. The sporophyte can produce haploid spores by meiosis that on germination produce a new generation of gametophytes.

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The ferns are a group of vascular plants that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissues that conduct water and nutrients and in having life cycles in which the branched sporophyte is the dominant phase.

<i>Psilotum</i> Genus of ferns in the family Psilotaceae

Psilotum is a genus of fern-like vascular plants. It is one of two genera in the family Psilotaceae commonly known as whisk ferns, the other being Tmesipteris. Plants in these two genera were once thought to be descended from the earliest surviving vascular plants, but more recent phylogenies place them as basal ferns, as a sister group to Ophioglossales. They lack true roots and leaves are very reduced, the stems being the organs containing photosynthetic and conducting tissue. There are only two species in Psilotum and a hybrid between the two. They differ from those in Tmesipteris in having stems with many branches and a synangium with three lobes rather than two.

<i>Huperzia</i> Genus of vascular plants

Huperzia is a genus of lycophyte plants, sometimes known as the firmosses or fir clubmosses; the Flora of North America calls them gemma fir-mosses. This genus was originally included in the related genus Lycopodium, from which it differs in having undifferentiated sporangial leaves, and the sporangia not formed into apical cones. The common name firmoss, used for some of the north temperate species, refers to their superficial resemblance to branches of fir (Abies), a conifer. As of 2020, two very different circumscriptions of the genus were in use. In the Pteridophyte Phylogeny Group classification of 2016, Huperzia is one of three genera in the subfamily Huperzioideae of the family Lycopodiaceae. Most species in the subfamily are placed in the genus Phlegmariurus. Huperzia is left with about 25 species, although not all have been formally transferred to other genera. Other sources recognize only Huperzia, which then has about 340 species.

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<span class="mw-page-title-main">Embryophyte</span> Subclade of green plants, also known as land plants

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The Marchantiophyta are a division of non-vascular land plants commonly referred to as hepatics or liverworts. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information.

<span class="mw-page-title-main">Hornwort</span> Division of non-vascular land plants with horn-shaped sporophytes

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<i>Platycerium</i> Genus of ferns

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<i>Crepidomanes intricatum</i> Species of fern

Crepidomanes intricatum, synonym Trichomanes intricatum, is known as the weft fern. The genus Crepidomanes is accepted in the Pteridophyte Phylogeny Group classification of 2016, but not by some other sources. As of October 2019, Plants of the World Online sank the genus into a broadly defined Trichomanes, treating this species as Trichomanes intricatum.

<i>Diplazium australe</i> Species of fern

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<i>Hymenophyllum australe</i> Species of fern

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<i>Asplenium <span style="font-style:normal;">×</span> trudellii</i> Species of fern

Asplenium × trudellii, commonly known as Trudell's spleenwort, is a rare hybrid fern of the eastern United States, first described in 1925. It is formed by the crossing of mountain spleenwort (A. montanum) with lobed spleenwort (A. pinnatifidum). Trudell's spleenwort is intermediate in form between its two parents, and is generally found near them, growing on exposed outcrops of acidic rock. While A. × trudellii is triploid and sterile, there is some evidence that it can occasionally reproduce apogamously.

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<i>Polyphlebium venosum</i> Species of fern

Polyphlebium venosum, the veined bristle-fern or bristle filmy fern, is a fern in the family Hymenophyllaceae. It is only found in wet forests, mainly growing as an epiphyte on the shady side of the soft tree fern, Dicksonia antarctica. It also grows on logs, trunks of trees and rarely on trunks of Cyathea species or on wet rock-faces. It is found in the wetter parts of Eastern Australia and New Zealand. P. venosum has poor long-distance dispersal compared to other ferns due to its short lived spore. Notable features of Polyphlebium venosum include it being one cell layer thick, 5–15 cm in length, having many branching veins and a trumpet shaped indusium.

References

  1. Farrar, Donald R.; Mickel, John T. (1991). "Vittaria appalachiana: A Name for the "Appalachian Gametophyte"". American Fern Journal. 81 (3): 69–75. doi:10.2307/1547574. ISSN   0002-8444. JSTOR   1547574.
  2. Pinson, Jerald B.; Schuettpelz, Eric (April 2016). "Unraveling the origin of the Appalachian gametophyte, Vittaria appalachiana". American Journal of Botany. 103 (4): 668–676. doi: 10.3732/ajb.1500522 . PMID   27033317.
  3. Farrar, Donald R. (April 2016). "Vittaria appalachiana continues to provide insight into the biology of ferns: A commentary on two studies recently published in American Journal of Botany". American Journal of Botany. 103 (4): 593–595. doi: 10.3732/ajb.1500323 . PMID   27056930 . Retrieved 13 December 2021.
  4. 1 2 3 Farrar, Donald R. (1993). "Vittaria appalachiana". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico. Vol. 2: Pteridophytes and Gymnosperms. New York and Oxford: Oxford University Press. Retrieved 7 February 2022.