Pilularia
Encyclopedia
Pilularia is a genus of unusual fern
s of family Marsileaceae
distributed in North Temperate regions, Ethiopia
n mountains, and the southern hemisphere in Australia
, New Zealand
, and western South America
.
Depending on the taxonomic revisor, the genus contains between 3 and 6 species of small plants with thread-like leaves, and creeping rhizomes. The sporangia are borne in spherical sporocarp
s ("pills") which form in the axils of leaves. Pilularia minuta from SW Europe is one of the smallest of all ferns.
, each chamber with sorus
bearing both macrosporangia and microsporangia
.
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
).
This is an internationally threatened species included in the European Red Data Book.
It is listed on Schedule 8 of the Wildlife (Northern Ireland) Order 1985, but it has not been seen 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.
Pillwort can be grown in a "bog garden" or as a marginal aquatic in a garden pond.
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
s of family Marsileaceae
Marsileaceae
The Marsileaceae are a small family of heterosporous aquatic and semi-aquatic ferns, though at first sight they do not physically resemble other ferns. The group is commonly known as the "pepperwort family" or as the "water-clover family" because the leaves of the genus Marsilea superficially...
distributed in North Temperate regions, Ethiopia
Ethiopia
Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...
n mountains, and the southern hemisphere in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, and western South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
.
Depending on the taxonomic revisor, the genus contains between 3 and 6 species of small plants with thread-like leaves, and creeping rhizomes. The sporangia are borne in spherical sporocarp
Sporocarp
Sporocarp can refer to any of several structures whose primary function is the production and release of spores.* Sporocarp , a multicellular structure on which spore-producing structures are borne....
s ("pills") which form in the axils of leaves. Pilularia minuta from SW Europe is one of the smallest of all ferns.
P. globulifera
Pilularia globulifera, or pillwort, is native to western Europe, where it grows at edges of lakes, ponds, ditches and marshes, on wet clay or clay-sand soil, sometimes in water up to 30cm deep. It has a pea-shaped 4-chambered sporocarpSporocarp
Sporocarp can refer to any of several structures whose primary function is the production and release of spores.* Sporocarp , a multicellular structure on which spore-producing structures are borne....
, each chamber with sorus
Sorus
A sorus is a cluster of sporangia .In fungi and lichens, the sorus is surrounded by an external layer. In some red algae it may take the form of a depression into the thallus....
bearing both macrosporangia and microsporangia
Microsporangia
Microsporangium is a sporangium that produces spores that give rise to male gametophytes. Microsporangia are notable in spikemosses, and a minority of ferns. In Gymnosperms and Angiosperms , the microsporangium produce the microsporocyte, also known as the microspore mother cell, which then creates...
.
Some of the plants growing in association with this species in the UK include water celery (Apium inundatum), marsh pennywort (Hydrocotyle vulgaris
Hydrocotyle vulgaris
Hydrocotyle vulgaris, also known as Marsh Pennywort, is a small creeping perennial herb native to N. Africa, Europe, Florida, and west to the Caspian region; in Britain it is the only native Hydrocotyle....
) and lesser spearwort (Ranunculus flammula
Ranunculus flammula
Ranunculus flammula L. is a species of perennial herbaceous plants in the genus Ranunculus , growing in damp places throughout the Boreal Kingdom. It is very closely related to R. reptans L., which is distinguished by prostrate and more slender stems, narrower leaves and smaller flowers and is...
).
This is an internationally threatened species included in the European Red Data Book.
It is listed on Schedule 8 of the Wildlife (Northern Ireland) Order 1985, but it has not been seen since 1970 and may now be extinct in the province. It is protected under the Wildlife and Countryside Act 1981
Wildlife and Countryside Act 1981
The Wildlife and Countryside Act 1981 is an Act of Parliament in the United Kingdom and was implemented to comply with the Directive 2009/147/EC on the conservation of wild birds...
in the rest of the UK, where it is now classified as Vulnerable.
Pillwort can be grown in a "bog garden" or as a marginal aquatic in a garden pond.