''Pilularia'' or pillworts is a genus of unusual

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except t ...

s of family

Marsileaceae Marsileaceae () is 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 ...

distributed in North Temperate regions,

Ethiopia Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the ...

n mountains, and the southern hemisphere in

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

, and western

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. 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 A sporangium (; from Late Latin, ) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other lineages form sporangia at some point in their life cy ...

are borne in spherical sporocarps ("pills") which form in the

axil A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

s of leaves. ''

Pilularia minuta ''Pilularia minuta'', is a species of fern belonging to the family Marsileaceae Marsileaceae () is a small family of heterosporous aquatic and semi-aquatic ferns, though at first sight they do not physically resemble other ferns. The group i ...

'' from SW Europe is one of the smallest of all ferns.

List of species

Recent work from Pryer Lab accepted four species of ''Pilularia'', with a fifth, ''P. novae-zealandiae'', being conspecific with ''P. novae-hollandiae''. In addition, another species, ''P. dracomontana'', has been described from

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

. * ''

Pilularia americana ''Pilularia americana'', the American pillwort, is an unusual species of fern. The fronds essentially consist of the petioles only, any form of flattened laminae having been lost. It is in the aquatic fern family Marsileaceae, and is related t ...

'' A.Braun (American pillwort) * ''

Pilularia globulifera ''Pilularia globulifera'', or pillwort, is an unusual species of fern in the family Marsileaceae. It is native to western Europe, where it grows at the edges of lakes, ponds, ditches and marshes, on wet clay or clay-sand soil, sometimes in water ...

'' L. (pillwort) * ''

'' Durieu (least pillwort) * ''

Pilularia novae-hollandiae ''Pilularia'' or pillworts is a genus of unusual ferns of family Marsileaceae distributed in North Temperate regions, Ethiopian mountains, and the southern hemisphere in Australia, New Zealand, and western South America. Depending on the taxono ...

'' A.Braun (austral pillwort) * ''

Pilularia dracomontana ''Pilularia'' or pillworts is a genus of unusual ferns of family Marsileaceae distributed in North Temperate regions, Ethiopian mountains, and the southern hemisphere in Australia, New Zealand, and western South America. Depending on the taxono ...

'' N. R. Crouch & J. Wesley-Smith (Dragon-Mountain pillwort)

References

UK Biodiversity Action Plan
* Preston, C.D. & Croft, J.M. (1997). ''Aquatic Plants in Britain and Ireland''. Harley Books, pp. 31–32.

External links

Salviniales Fern genera {{Polypodiidae-stub