''Tmesipteris obliqua,'' more commonly known as the long fork-fern or common fork-fern, is a weeping,

epiphytic An epiphyte is an organism that grows on the surface of a 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 epiphytes grow are called phoroph ...

fern ally Fern allies are a diverse group of seedless vascular plants that are not true ferns. Like ferns, a fern ally disperses by shedding spores to initiate an alternation of generations. Classification Originally, three or four groups of plants were ...

with narrow unbranched leafy stems. ''T. obliqua'' is a member of the genus ''

Tmesipteris ''Tmesipteris'', the hanging fork ferns, is a genus of ferns, one of two genera in the family Psilotaceae, order Psilotales (the other being ''Psilotum''). ''Tmesipteris'' is restricted to certain lands in the Southern Pacific, notably Australia, ...

'', commonly known as hanging fork-ferns. ''

'' is one of two genera in the order ''Psilotales,'' the other genus being ''

Psilotum ''Psilotum'' is a genus of fern-like vascular plants. It is one of two genera in the family Psilotaceae commonly known as whisk ferns, the other being ''Tmesipteris''. Plants in these two genera were once thought to be descended from the earlies ...

''. ''T. obliqua'' is endemic to eastern

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 ...

Anatomy and biology

''T. obliqua'' is a weeping,

that grows on trunks of

tree fern The tree ferns are arborescent (tree-like) ferns that grow with a trunk elevating the fronds above ground level, making them trees. Many extant tree ferns are members of the order Cyatheales, to which belong the families Cyatheaceae (scaly tree ...

s, such as ''

Dicksonia antarctica ''Dicksonia antarctica'', the soft tree fern or man fern, is a species of evergreen tree fern native to eastern Australia, ranging from south-east Queensland, coastal New South Wales and Victoria to Tasmania. Anatomy and biology These ferns ...

'' and some rocky surfaces. Fronds of ''T. obliqua'' are unbranched and grow to 20-65cm in length. ''T. obliqua'' has a thick fleshy

rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

but no true roots. This rhizome is brittle and resents disturbance. The stems are usually without branches and smooth at the base, except for a single groove on the upper surface of the lower section of stem. Leaves are oblong in shape, sometimes broad as well, and are roughly 20-30mm in length, 4-8mm wide. Leaves are not crowded (c. 3 per cm), are asymmetrical at the base and apex truncate with a fine excurrent point. Leaves reduce in size towards apex of stem (younger parts of the plant are smaller). ''T. obliqua'' are non-flowering and spore forming. Sporangia are borne in pointed 2-chambered capsules at the base of specialise forked bracts, which are narrower and shorter than sterile leaves. It has been discovered that ''Tmesipteris obliqua'' has the largest known fern genome (1C = 150.61 pg). Its genome size was estimated by flow cytometry in comparison with the genome of ''

Paris japonica is a Japanese species of plants in the genus ''Paris'' in the family Melanthiaceae.Ohwi, J. (1984). Flora of Japan (in English): 1-1067. Smithsonian Institution, Washington, D.C.. It is native to sub-alpine regions of Japan. A slow growing per ...

'' (Melanthiaceae; 1C = 152.23 pg), the largest genome so far reported for any eukaryote. This discovery has shown a double in genome size compared to genome size values previously encountered in ferns.

Distribution and Habitat

''Tmesipteris obliqua'' is an

epiphyte An epiphyte is an organism that grows on the surface of a 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 epiphytes grow are called phoroph ...

commonly found growing on the trunks of tree-ferns, especially the soft tree-fern, ''

'' and occasionally shady, moist rock-faces. Tmesipteris obliqua Long Fork Fern Mount Dromedary southern New South Wales

This species is widespread and common from sea level up to 600m in communities of fern gullies,

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

s and wet sclerophyll forests. ''T. obliqua'' thrives in moist, shady, humid and rocky environments and soil tolerances include mossy logs, rock or soil amongst exposed roots. ''T. obliqua'' is most commonly found distributed along eastern

Cultivation

Due to its epiphytic nature, ''T. obliqua'' grows best in areas of high rainfall, large amounts of shade and some humidity in communities with rocky surfaces. These very specific growth requirements, plus the delicacy of the species, makes it extremely difficult for cultivation.

References

{{Taxonbar, from=Q17250493 Psilotaceae Flora of New South Wales Flora of Victoria (Australia) Flora of Tasmania Epiphytes