Pilularia globulifera

Pilularia globulifera
Scientific classification
Kingdom:Plantae
Division:Pteridophyta
Class:Polypodiopsida/Pteridopsida
(disputed)
Order:Salviniales
Family:Marsileaceae
Genus:Pilularia
Species: P. globulifera
Binomial name
Pilularia globulifera

Pilularia globulifera, or pillwort,[2] is an unusual species of fern native to western Europe,[3] where it grows at edges of lakes, ponds, ditches and marshes, on wet clay or clay-sand soil, sometimes in water up to 30 cm (12 in) deep.

Description

It has a pea-shaped 4-chambered sporocarp, each chamber formed from a modified leaf and containing several sori bearing both macrosporangia and microsporangia. The species is thus heterosporous.

Habitat

Pillwort grows on silt and mud at the margins of lakes, ponds and other watercourses that are submerged for at least part of the year.[4]:16 Some of the plants growing in association with this species in the UK include water celery (Apium inundatum), marsh pennywort (Hydrocotyle vulgaris) and lesser spearwort (Ranunculus flammula).

Distribution

This is a rare species, declining as its wetland habitats are reduced by eutrophication and drainage, but is regarded as of least concern by the IUCN Red List. It is listed on Schedule 8 of the Wildlife (Northern Ireland) Order 1985, but it has not been seen there since 1970 and may now be extinct in the province. It is protected under the Wildlife and Countryside Act 1981 in the rest of the UK, where it is now classified as Vulnerable.

Uses

Pillwort can be grown in a "bog garden" or as a marginal aquatic in a garden pond.

References

  1. ↑ Christenhusz, M., Lansdown, R.V., Bento Elias, R., Dyer, R., Ivanenko, Y., Rouhan, G., Rumsey, F. & Väre, H. (2017). "Pilularia globulifera". The IUCN Red List of Threatened Species. IUCN. 2017: e.T167887A85436052. doi:10.2305/IUCN.UK.2017-2.RLTS.T167887A85436052.en. Retrieved 15 January 2018.
  2. ↑ "BSBI List 2007". Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-01-25. Retrieved 2014-10-17.
  3. ↑ Lansdown, R.V. (2011). "Pilularia globulifera". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 28 August 2012.
  4. ↑ Stace, C. A. (2010). New Flora of the British Isles (Third ed.). Cambridge, U.K.: Cambridge University Press. ISBN 9780521707725.


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