Prionium serratum
| Prionium serratum | |
|---|---|
 | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Monocots |
| (unranked): | Commelinids |
| Order: | Poales |
| Family: | Thurniaceae |
| Binomial name | |
| Prionium serratum Drège | |
Prionium serratum (L.f.) Drège aka Palmiet is a robust, evergreen, semi-aquatic, rhizomatous, endemic South African plant growing to some 2 m in height.
Its stem is up to 100 mm in diameter and covered with the black, fibrous bases of old spirally-arranged leaves, four-ranked or tristichous, as in the closely related family of Juncaceae, a family in which it was previously placed - it also has close affinities with the Bergpalmiet (Tetraria thermalis) in Cyperaceae. 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 1m in length. Plants are hermaphroditic and pollination is anemophilous. The fruit is a dry dehiscent triangular capsule, with 3 seed chambers and arillate seeds which are hispid (with sclerenchymatous fibres) and winged. [1][2] The black fibrous leaf bases are often found on beaches near rivers with colonies of palmiet. (see illustration)
This is one of only four species in the family Thurniaceae and the only member of the family native to southern Africa. This species has a disjunct distribution 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'. [3] The name 'wilde palmit' was used by Jan van Riebeeck 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 in about 1772. The name evolved into 'wilde palmiet' and then 'palmiet'. Several rivers in the Western Cape have have been named Palmiet River for this species growing along their courses - two of the larger ones are the Palmiet River mouthing between Betty's Bay and Kleinmond, and one having its source just west of Formosa Peak and eventually joining the Keurbooms River.
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