''Tmesipteris truncata'' (aka ''Tmesipteris oblanceolata'') is a

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 ...

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to eastern

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. It is commonly called a Fork Fern. The habitat of this primitive plant is under waterfalls, or in

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

gullies or

rainforest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...

s. It is often found growing on the base of the King Fern. Usually seen as an

epiphyte An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

lithophyte Lithophytes are plants that grow in or on rocks. They can be classified as either epilithic (or epipetric) or endolithic; epilithic lithophytes grow on the surfaces of rocks, while endolithic lithophytes grow in the crevices of rocks (and are als ...

, but it may also appear as a terrestrial plant. It is found as far south as

Mount Dromedary Gulaga, dual-named as Mount Dromedary and also referred to as Mount Gulaga, is a mountain located in the south coast region of New South Wales, Australia. It rises above the village of Central Tilba and is within the Gulaga National Park. At ...

. The stems are 15 to 30 cm long, mostly unbranched. Three or four grooves are at the base. The leaves grow shorter at the base, also shorter at the apex of the stems. Leaves are narrow linear to oblong in shape; 15 to 25 mm long, 2 to 5 mm wide. The midvein of the leaf ends in a thin point.

Synangia A sporangium (from Late Latin, ; : sporangia) 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 groups form sporangia at some point in their lif ...

are 3 to 5 mm long. The specific epithet ''truncata'' refers to the leaf tops, which appear abruptly cut off.Les Robinson - Field Guide to the Native Plants of Sydney, page 303 This plant first appeared in scientific literature in 1810 as ''Psilotum truncatum'' in the ''

Prodromus Florae Novae Hollandiae ''Prodromus Florae Novae Hollandiae et Insulae Van Diemen'' (Prodromus of the Flora of New Holland and Van Diemen's Land) is a book by the botanist Robert Brown Robert Brown may refer to: Robert Brown (born 1965), British Director, Animator and ...

'', authored by the prolific Scottish botanist,

Robert Brown Robert Brown may refer to: Robert Brown (born 1965), British Director, Animator and author Entertainers and artists * Washboard Sam or Robert Brown (1910–1966), American musician and singer * Robert W. Brown (1917–2009), American printmaker ...

. On 31 May 2024, ''Tmesipteris oblanceolata'' was reported to have been found to contain the largest known eukaryotic

genome A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...

, with 160 billion

base pair A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...

s, by comparison more than 50 times larger than the

human genome The human genome is a complete set of nucleic acid sequences for humans, encoded as the DNA within each of the 23 distinct chromosomes in the cell nucleus. A small DNA molecule is found within individual Mitochondrial DNA, mitochondria. These ar ...

References

{{Taxonbar, from=Q7810769 Psilotaceae Flora of New South Wales Flora of Queensland Epiphytes Plants described in 1810

See also

References