Anchistea

Anchistea is a genus of leptosporangiate ferns in the family Blechnaceae. It has only one species, Anchistea virginica (synonym Woodwardia virginica) the Virginia chain fern, which has long creeping, scaly, underground stems or rhizomes giving rise to tall (up to about 4 feet, 120 centimetres) 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 (alternation of generations) 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.

Virginia chain fern
Sori

Secure  (NatureServe)[1]
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Order: Polypodiales
Suborder: Aspleniineae
Family: Blechnaceae
Genus: Anchistea
C.Presl[2]
Species:
A. virginica
Binomial name
Anchistea virginica
(L.) C.Presl[2]
Synonyms[2][3]
  • Blechnum virginicum L.
  • Woodwardia virginica (L.) Sm.

Taxonomy and evolution

Anchistea virginica was first described by Carl Linnaeus in 1771 as Blechnum virginicum.[4] It was transferred to Woodwardia by James Edward Smith in 1793,[5] and to Anchistea by Carl Presl in 1851.[2][6] Some sources retain it in Woodwardia,[3] but the Pteridophyte Phylogeny Group classification of 2016 (PPG I) retains Presl's genus, making it the sole species in Anchistea.[2]

Fossils of Anchistea virginica have been described from the Middle Miocene of the U.S. states of Washington and Mississippi, suggesting its range was probably once much more widespread in North America.[7][8] In the Middle Miocene, Anchistea virginica apparently occupied similar habitats as in the present day.

Distribution

Endemic to eastern North America from Florida to Nova Scotia and west to Michigan and Illinois. A. virginica is mostly found on the Atlantic coastal plain and Piedmont although it also grows in the eastern Great Lakes region as far west as Illinois. The Flora of North America website has a distribution map.

Ecology and conservation

Anchistea virginica grows in the wet soils of open wet swampy woods, acid bogs, and along streams and roadside ditches,[9] avoiding calcareous substrates. A. virginica is an important constituent of the field layer of flatwoods, Atlantic white cedar (Chamaecyparis thyoides) swamp forest and bay (Magnolia virginiana) forests.[10]

Cultivation and uses
Detail of frond

The plant is occasionally cultivated as a greenhouse or garden ornamental. Hardy to USDA Zone 3.

References
  1. "NatureServe Explorer 2.0 Woodwardia virginica Virginia Chainfern". explorer.natureserve.org. Retrieved 5 October 2020.
  2. PPG I (2016). "A community-derived classification for extant lycophytes and ferns". Journal of Systematics and Evolution. 54 (6): 563–603. doi:10.1111/jse.12229. S2CID 39980610.
  3. "Woodwardia virginica (L.) Sm.". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2019-08-09.
  4. "Blechnum virginicum L." The International Plant Names Index. Retrieved 2019-08-09.
  5. "Woodwardia virginica (L.) Sm". The International Plant Names Index. Retrieved 2019-08-09.
  6. "Anchistea virginica (L.) C.Presl". The International Plant Names Index. Retrieved 2019-08-09.
  7. Pigg, K. B.; Rothwell, G. W. (2001). Anatomically Preserved Woodwardia virginica (Blechnaceae) and a New Filicalean Fern from the Middle Miocene Yakima Canyon Flora of Central Washington, USA.
  8. McNair, D.M.; D.Z. Stults; B. Axsmith; M.H. Alford; J.E. Starnes (2019). "Preliminary investigation of a diverse megafossil floral assemblage from the middle Miocene of southern Mississippi, USA" (PDF). Palaeontologia Electronica. doi:10.26879/906.
  9. McVaugh, R.; Pyron, J. H. (1951). Ferns of Georgia. Athens, Georgia: University of Georgia Press.
  10. Barbour, M. G.; Billings, W. D. (2000). North American Terrestrial Vegetation (2nd ed.). Cambridge: Cambridge University Press.

Further reading
  • Barbour, M. G., and Billings, W. D. (2000). North American Terrestrial Vegetation. 2nd Edition. Cambridge University Press, Cambridge.
  • Cobb, B. (1984). A Field Guide to Ferns and their Related Families of Northeastern and Central North America. Peterson Field Guides.
  • Gleason, H. A. and Cronquist, A. (1963). Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Van Nostrand, New York.
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