Regnellidium is a monotypic genus of
fern
The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...
s of family
Marsileaceae.
The single living species, ''Regnellidium diphyllum'', the two-leaf water fern, is native to southeastern Brazil and adjacent regions of Argentina. It resembles its relatives from the genus ''
Marsilea'', but has 2-lobed leaves (rather than 4). This fern is sometimes grown in aquaria.
A fossil assigned to the species ''
Regnellidium upatoiensis'' has been found in
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...
deposits of the eastern
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
.
The genus name of ''Regnellidium'' is in honour of
Anders Fredrik Regnell (1807–1884), a Swedish physician and botanist.
It was first described and published in Ark. Bot. Vol.3 (Issue 6) on page 2 in 1904.
References
Other sources
*
Mabberley, D. J. (1997). ''The Plant-Book''. Cambridge University Press.
Salviniales
Flora of Brazil
Monotypic fern genera
Plants described in 1904
{{Polypodiidae-stub