Vandenboschia boschiana

Last updated

Appalachian bristle fern
Vandenboschia boschiana.jpg
Status TNC G4.svg
Apparently Secure  (NatureServe) [1]
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Order: Hymenophyllales
Family: Hymenophyllaceae
Genus: Vandenboschia
Species:
V. boschiana
Binomial name
Vandenboschia boschiana
(J.W.Sturm ex Bosch) Ebihara & K.Iwats. [2]
Synonyms [2]
  • Trichomanes boschianumJ.W.Sturm

Vandenboschia boschiana, synonym Trichomanes boschianum, [2] also known as the Appalachian bristle fern [3] or Appalachian filmy fern, is a small delicate perennial leptosporangiate fern which forms colonies with long, black creeping rhizomes.

Contents

Description

The evergreen fronds are bipinnatifid, deeply and irregularly dissected, about 4 to 20 cm long, 1 to 4 cm across with winged stipes 1 to 7 cm long and light green in colour. The common name derives from the leaves which are very thin, only a single cell thick, missing an epidermis and translucent, giving the appearance of a wet film.

Sori, the spore-producing organs are formed along the margins of the frond segments. The indusium forms a funnel around the sorus which is sunken in the leaf tissue. A bristle-like receptacle protrudes from the indusium as in all Trichomanes species. Spore production occurs between July and September.

In common with all ferns, V. boschiana exhibits a gametophyte stage in its life cycle (alternation of generations) and develops a haploid reproductive prothallus as an independent plant. In contrast to the typical heart-shaped fern prothallus, V. boschiana gametophytes are filamentous and resemble colonies of green algae or moss protonemata.

Taxonomy

According to the Flora of North America ploidy is rather variable. The western colonies tend to be diploid whilst the eastern ones are mostly tetraploid. Sterile triploids have also been recorded.

It has been hypothesized that most of the populations of V. boschiana are genetically identical clones of great age. [4]

Distribution

It is endemic to eastern North America. Populations are found in the eastern United States from southern Ohio in the north to Alabama in the south and from Arkansas and southern Illinois in the west to South Carolina in the east. In all areas the populations are very scattered and reflect the distribution of an uncommon habitat.

Ecology and conservation

Vandenboschia boschiana is found in deep shade on damp acid rocks, usually sandstone, of sheltered canyons, grottos and rock shelters at an altitude of 150 to 800 m. The rock outcrops are generally found within mesic upland forests. [4]

This fern is dependent upon a constantly high air humidity which places severe restrictions on its distribution in the current climate of eastern North America. In fact V. boschiana is believed to be a relict of milder pre-glacial conditions. [4] The current distribution of V. boschiana is considered to reflect historical lack of glaciation, substrate, type of bedrock, lack of disturbance in the surrounding forest and micro-climate. Temperature is perhaps less important than these factors though extreme cold weather can apparently cause mortality. [5] Periodic droughts do cause heavy mortality and have reduced many population sizes over the last few decades. [6]

The species is probably more at risk than its G4 grading would suggest and state NatureServe conservation rankings are Vulnerable (S3) to Critically imperiled (S1).

Hazards include drying of the habitat, removal of forest canopy shading the rock exposures and over-collecting. [5]

Cultivation and uses

The plant is not known to be widely cultivated. From its large-scale distribution the plant may be hardy to USDA Zone 6, although this may not reflect the micro-climate of its sheltered habitat.

Related Research Articles

<i>Gymnocarpium dryopteris</i> Species of fern

Gymnocarpium dryopteris, the western oakfern, common oak fern, oak fern, or northern oak fern, is a deciduous fern of the family Cystopteridaceae. It is widespread across much of North America and Eurasia. It has been found in Canada, the United States, Greenland, China, Japan, Korea, Russia, and most of Europe. It is a seedless, vascular plant that reproduces via spores and have a life cycle with alternating, free-living sporophyte and gametophyte phases.

<span class="mw-page-title-main">Hymenophyllaceae</span> Family of ferns

The Hymenophyllaceae, the filmy ferns and bristle ferns, are a family of two to nine genera and about 650 known species of ferns, with a subcosmopolitan distribution, but generally restricted to very damp places or to locations where they are wetted by spray from waterfalls or springs. A recent fossil find shows that ferns of Hymenophyllaceae have existed since at least the Upper Triassic.

<i>Trichomanes</i> Genus of ferns

Trichomanes is a genus of ferns in the family Hymenophyllaceae, termed bristle ferns. The circumscription of the genus is disputed. All ferns in the genus are filmy ferns, with leaf tissue typically 2 cells thick. This thinness generally necessitates a permanently humid habitat, and makes the fronds somewhat translucent. Because of this membrane-like frond tissue, the plant is prone to drying out. “Filmy ferns” in the taxa Hymenophyllaceae grow in constantly wet environments. Many are found in cloud forests such as “Choco” in Colombia. There are also members of the taxa that can grow submersed in water.

<i>Asplenium rhizophyllum</i> Species of fern in the family Aspleniaceae

Asplenium rhizophyllum, the (American) walking fern, is a frequently-occurring fern native to North America. It is a close relative of Asplenium ruprechtii which is found in East Asia and also goes by the common name of "walking fern".

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

Hymenophyllum nephrophyllum, the kidney fern, is a filmy fern species native to New Zealand. It commonly grows on the forest floor of open native bush. Individual kidney-shaped fronds stand about 5–10 cm tall. In hot weather they shrivel up to conserve moisture, but open up again when the wet returns. This species has very thin fronds which are only four to six cells in thickness. In the Māori language they are also called raurenga.

<i>Vandenboschia speciosa</i> Species of fern

Vandenboschia speciosa, synonym Trichomanes speciosum, commonly known as the Killarney fern, is a species of fern found widely in Western Europe. It is most abundant in Ireland, Great Britain, Brittany, Galicia, Canary Islands, Madeira and the Azores, but is also found in other locations including France, Spain, Portugal and Italy. It is a relict endemic European species with a disjunct distribution, having had a much wider distribution before the climate changes of the Tertiary and Quaternary periods.

<i>Asplenium trichomanes</i> Species of fern in the family Aspleniaceae

Asplenium trichomanes, the maidenhair spleenwort, is a small fern in the spleenwort genus Asplenium. It is a widespread and common species, occurring almost worldwide in a variety of rocky habitats. It is a variable fern with several subspecies.

<i>Amauropelta noveboracensis</i> Species of fern

Amauropelta noveboracensis, the New York fern, is a perennial species of fern found throughout the eastern United States and Canada, from Louisiana to Newfoundland, but most concentrated within Appalachia and the Atlantic Northeast. New York ferns often forms spreading colonies within the forests they inhabit.

<i>Diphasiastrum digitatum</i> Species of plant

Diphasiastrum digitatum is known as groundcedar, running cedar or crowsfoot, along with other members of its genus, but the common name fan clubmoss can be used to refer to it specifically. It is the most common species of Diphasiastrum in North America. It is a type of plant known as a clubmoss, which is within one of the three main divisions of living vascular plants. It was formerly included in the superspecies Diphasiastrum complanatum. For many years, this species was known as Lycopodium flabelliforme or Lycopodium digitatum.

<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>Polystichum lonchitis</i> Species of fern

Polystichum lonchitis is a species of fern known by the common name northern hollyfern, or simply holly-fern. It is native to much of the Northern Hemisphere from Eurasia to Alaska to Greenland and south into mountainous central North America. It has stiff, glossy green, erect fronds and grows in moist, shady, rocky mountain habitats.

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

Hymenophyllum australe, commonly known as austral filmy fern, is a relatively large rupestral and epiphytic fern, indigenous to eastern Australia and New Zealand. It belongs to the unique Hymenophyllum genus, which are characterised by their thin membranous fronds that are seldom more than one cell thick, with the exception of regions over and around veins. Hymenophyllum australe is distinctive in that the fronds are typically thicker than other Hymenophyllum species, often being up to 2-3 cells thick.

<i>Polystichum vestitum</i> Species of fern

Polystichum vestitum, commonly known as the prickly shield fern or pūnui (Maori), is a hardy, evergreen or semi-evergreen ground fern.

<i>Dendrolycopodium obscurum</i> Species of spore-bearing plant

Dendrolycopodium obscurum, synonym Lycopodium obscurum, commonly called rare clubmoss, ground pine, or princess pine, is a North American species of clubmoss in the family Lycopodiaceae. It is a close relative of other species such as D. dendroideum and D. hickeyi, also treelike. It is native to the eastern United States and southeastern Canada from Georgia to Minnesota to Nova Scotia. It grows in the understory of temperate coniferous and deciduous forests, where it is involved in seral secondary succession, growing in clonal colonies some years after disturbance has occurred. It has also been found in Japan, Taiwan, Korea, Russian Far East, and northeastern China.

<i>Gymnocarpium robertianum</i> Species of fern

Gymnocarpium robertianum, the limestone fern or scented oakfern, is a fern of the family Cystopteridaceae.

<i>Adiantum viridimontanum</i> Species of fern

Adiantum viridimontanum, commonly known as Green Mountain maidenhair fern, is a fern found only in outcrops of serpentine rock in New England and Eastern Canada. The leaf blade is cut into finger-like segments, themselves once-divided, which are borne on the outer side of a curved, dark, glossy rachis. These finger-like segments are not individual leaves, but parts of a single compound leaf. The "fingers" may be drooping or erect, depending on whether the individual fern grows in shade or sunlight. Spores are borne under false indusia at the edge of the subdivisions of the leaf, a characteristic unique to the genus Adiantum.

<i>Anchistea</i> Genus of ferns

Anchistea is a genus of leptosporangiate ferns in the family Blechnaceae. It has only one species, Anchistea virginica the Virginia chain fern, which has long creeping, scaly, underground stems or rhizomes giving rise to tall widely separated, deciduous, single leaves. In contrast, the leaves of Osmundastrum cinnamomeum, which can be mistaken for A. virginica, grow in a group from a crown. Also in contrast to O. cinnamomeum the leaves are monomorphic without distinct fertile fronds. The lower petiole or stipe is dark purple to black, shiny and swollen, the upper rachis is dull green. The leaf blade is green and lanceolate, composed of 12 to 23 paired, alternate pinnatifid pinnae. The pinnae are subdivided into 15 to 20 paired segments that are ovate to oblong. The lower rachis is naked for about half its length. The sori or spore-producing bodies are found on the underside of the pinnae and are long and form a double row which outlines the major veins of the pinnae. In common with all ferns, A. virginica exhibits a gametophyte stage in its life cycle and develops a haploid reproductive prothallus as an independent plant. The spores are produced in red-brown sori which line the spaces (areolae) between the costa and costules. Further photographs can be found at the Connecticut Botanical Society and Ontario Ferns websites.

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

Hymenophyllum tunbrigense, the Tunbridge filmy fern or Tunbridge filmy-fern, is a small, fragile perennial leptosporangiate fern which forms large dense colonies of overlapping leaves from creeping rhizomes. The common name derives from the leaves which are very thin, only a single cell thick, and translucent, giving the appearance of a wet film. The evergreen fronds are bipinnatifid, deeply and irregularly dissected, about 3 to 6 cm long, 2 cm across with dark winged stipes. In contrast to the similar H. wilsonii the fronds are more divided, flattened, appressed to the substrate and tend to have a bluish tint.

<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 antartica. 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.

<i>Hymenophyllum rarum</i> Species of plant

Hymenophyllum rarum, the narrow filmy-fern, is a species of fern from the family Hymenophyllaceae. This thin-leaved fern is commonly found in New Zealand and Tasmania, growing in patches on rocks and is epiphytic on trees and tree ferns, growing in moist gullies or rainforests. A rather drought tolerant species often found at exposed sites ranging from coastal to montane areas. Forming extensive, interwoven and creeping patches with its thin long (creeping) rhizomes sparsely covered in red-brown hairs, easily recognised by its membranous grey-green fronds, the smooth margins of the pinnae, ultimate segments and indusia; and by the sunken sori in the uppermost segments of the uppermost pinnae. The species can be found throughout Tasmanian rainforests as well as occurring in New South Wales, Victoria and New Zealand on the North and South Islands as well as, Stewart, Chatham and Auckland Islands.

References

  1. https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.133119/Trichomanes_boschianum
  2. 1 2 3 Hassler, Michael & Schmitt, Bernd (August 2019). "Vandenboschia boschiana". Checklist of Ferns and Lycophytes of the World. 8.10. Retrieved 2019-10-08.
  3. USDA, NRCS (n.d.). "Trichomanes boschianum". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 14 December 2015.
  4. 1 2 3 Hill, S.R. (2003). Conservation Assessment for Appalachian Bristle Fern (Trichomanes boschianum) Sturm. USDA Forest Service, Eastern Region
  5. 1 2 Cusick, A. (1983). Trichomanes boschianum in Ohio. Ohio DNR
  6. Farrar, D.R. (1993). Hymenophyllaceae, In: Flora of North America Editorial Committee, eds., Flora of North America, Vol. 2. Oxford University Press. New York.

Further reading