''Prionium serratum'', the palmiet, is a robust, evergreen, semiaquatic,

rhizomatous 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 ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

growing to in height. It is the only species in the genus ''Prionium'', and is

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 ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

(

Cape Province The Province of the Cape of Good Hope (), commonly referred to as the Cape Province () and colloquially as The Cape (), was a province in the Union of South Africa and subsequently the Republic of South Africa. It encompassed the old Cape Co ...

and

KwaZulu-Natal KwaZulu-Natal (, also referred to as KZN) is a Provinces of South Africa, province of South Africa that was created in 1994 when the government merged the Zulu people, Zulu bantustan of KwaZulu ("Place of the Zulu" in Zulu language, Zulu) and ...

).Kew World Checklist of Selected Plant Families
/ref> Some authors have separated ''Prionium'' from the

Thurniaceae The Thurniaceae are a family of flowering plants composed of two genera with four species. The botanical name has been recognized by most taxonomists. The APG II system, of 2003, also recognizes such a family, and assigns it to the order Poales ...

, putting it instead in its own family, the Prioniaceae.

Description

The stem of ''P. serratum'' is up to in diameter and covered with the black, fibrous bases of old spirally arranged leaves, four-ranked or tristichous, as in the closely related family

Juncaceae Juncaceae is a family of flowering plants, commonly known as the rush family. It consists of 8 genera and about 464 known species of slow-growing, rhizomatous, herbaceous monocotyledonous plants that may superficially resemble grasses and ...

, a family in which it was previously placed - it also has close affinities with the bergpalmiet ('' Tetraria thermalis'') in the

Cyperaceae The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as wikt:sedge, sedges. The family (biology), family is large; botanists have species description, described some 5,500 known species in about 90 ...

. The strap-like lanceolate leaves are rigid, with a high silica content, narrow, leathery, grey-green, and with toothed margins. The small, brown flowers are on a branched inflorescence about 1 m in length. Plants are hermaphroditic and pollination is

anemophilous Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges, and rushes. Other common anemophilous pla ...

. The fruit is a dry dehiscent triangular capsule, with three seed chambers and

arillate An aril (), also called arillus, is a specialized outgrowth from a seed that partly or completely covers the seed. An arillode, or false aril, is sometimes distinguished: whereas an aril grows from the attachment point of the seed to the ova ...

seeds which are hispid (with sclerenchymatous fibres) and winged. The net-like, black fibrous, reticulate leaf sheaths are often found on beaches near rivers with colonies of palmiet (see Gallery). New flower shoots are cooked as vegetables.

Taxonomy and distribution

''P. serratum'' is one of only four species in the family

and the only member of the family native to southern Africa. This species has a

disjunct distribution In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but considerably separated from each other geographically. The causes are varied and might demonstrate either the expansion or contraction of a s ...

along the southern and south-eastern seaboard from the Western Cape to KwaZulu-Natal on sandstone substrates, growing in dense mats in marshy areas, and in and along streams and rivers. Palmiet wetlands are ecosystems that greatly reduce the erosive damage done by floodwater. When palmiet is removed, streams may become choked by sediment and banks eroded by unchecked floodwater. ''Prionium'' is from the Greek for sawblade, while ''serratum'' is Latin for toothed.PlantZAfrica.com
/ref> The name ' was used by

Jan van Riebeeck Johan Anthoniszoon "Jan" van Riebeeck (21 April 1619 – 18 January 1677) was a Dutch navigator, ambassador and colonial administrator of the Dutch East India Company. Life Early life Jan van Riebeeck was born in Culemborg on 21 April ...

for this plant, doubtless because of its close resemblance to palmito and the palmettos, and it was first noted by the Swedish botanist

Carl Peter Thunberg Carl Peter Thunberg, also known as Karl Peter von Thunberg, Carl Pehr Thunberg, or Carl Per Thunberg (11 November 1743 – 8 August 1828), was a Sweden, Swedish Natural history, naturalist and an Apostles of Linnaeus, "apostle" of Carl Linnaeus ...

in about 1772. The name evolved into wilde palmiet and then palmiet. Several rivers in the Western Cape have been named Palmiet River for this species growing along their courses - two of the larger ones are the

Palmiet River Palmiet River () is a river located in the Western Cape province of South Africa. The Palmiet River is a typical Western Cape river, experiencing winter rainfall and it is important for the Western Cape Water Supply System. It has a small catchme ...

mouthing between

Betty's Bay Betty's Bay is a small holiday town situated on the Overberg coast of South Africa's Western Cape province. It is located 100 km from Cape Town beneath the Kogelberg Mountains on the scenic R44 ocean drive between Pringle Bay and Kleinmond. ...

and

Kleinmond Kleinmond is a small coastal town in the Overberg region of the Western Cape province, South Africa. It is situated inside a UNESCO-declared Man and the Biosphere Programme, biosphere about 90 km east of Cape Town between Betty's Bay and Herm ...

, and one having its source just west of

Formosa Peak Formosa Peak or Peak Formosa is the highest point of the Tsitsikamma Mountains, a coastal range located along the Garden Route in South Africa, and forming part of the Baviaanskloof Mega Reserve. Background The peak was first mapped in 1576 ...

and eventually joining the

Keurbooms River The Keurbooms River () is a river in the Western Cape Province in South Africa. The river has its sources south of Uniondale, Western Cape, Uniondale in the Langkloof and flows in a roughly southeastern direction. It passes De Vlugt and the Prin ...

Gallery

Prionium serratum11.jpg Prionium serratum.jpg, Prionium serratum06.jpg, Prionium serratum01a.jpg, Prionium serratum04.jpg,

References

External links

Image of flowersFibrous tissuePalmiet River
{{Taxonbar, from=Q3019520 Thurniaceae Aquatic plants Monotypic Poales genera