Halimeda
| Halimeda | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the family | ||||||||||||
| Halimedaceae | ||||||||||||
| Link , 1832 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Halimeda | ||||||||||||
| Jean Vincent Félix Lamouroux , 1812 |
Halimeda is a genus of tang-forming green algae with a pearl-like thallus made of calcified, disc-shaped segments. It occurs mainly in warm seas. There, the limestone sediments produced by Halimeda contribute significantly to the formation of the reef .
description
The thallus consists of calcified, flat, disk-shaped segments that alternate like a string of pearls with uncalcified "joints" (nodes). It is attached to the ground with a root-like network or a tuber. Its growth form is upright, hanging or spread out, its size reaches a few centimeters to over a meter depending on the species. The shape of the segments is species-specific, for example they can be rounded, kidney-shaped, triangular, cylindrical, simple or lobed. The lime is deposited in the form of aragonite needles . Like all Bryopsidales, Halimeda is siphonally organized : the thallus consists of filaments without transverse walls, i.e. a single multinucleated cell.
The life cycle is that of a monophasic haplont , there is only one vegetative phase with haploid nuclei. Sexual reproduction takes place holocarpically , so the whole thallus is transformed into the fruiting body. After the formation of the two-flagged gametes , the thallus dies. Also, can Halimeda asexually reproduce by fragmentation.
Occurrence
Halimeda is mainly found in tropical seas. Some species also occur subtropically , one species ( Halimeda tuna ) also lives in the Mediterranean . The algae grow firmly ( benthic ) from the shallow tidal range to a water depth of 150 m.
Systematics
Halimeda was described by Jean Vincent Félix Lamouroux in 1812 , with the type species Halimeda tuna . According to Algaebase, the genus comprises around 43 species: it is one of the best-researched examples of cryptospecies .
- Halimeda bikinensis
- Halimeda borneensis
- Halimeda coreidesmis
- Halimeda copiosa
- Halimeda cryptica
- Halimeda cuneata
- Halimeda cylindracea
- Halimeda discoidea
- Halimeda distorta
- Halimeda favulosa
- Halimeda floridiana
- Halimeda fragilis
- Halimeda gigas
- Halimeda goreauii
- Halimeda gracilis
- Halimeda heteromorpha
- Halimeda howensis
- Halimeda hummii
- Halimeda incrassata
- Halimeda kanaloana
- Halimeda lacrimosa
- Halimeda lacunalis
- Halimeda macroloba
- Halimeda macrophysa
- Halimeda magnidisca
- Halimeda melanesica
- Halimeda micronesica
- Halimeda minima
- Halimeda monile
- Halimeda opuntia
- Halimeda peltata
- Halimeda pumila
- Halimeda pygmaea
- Halimeda rectangularis
- Halimeda renschii
- Halimeda scabra
- Halimeda sertolara
- Halimeda simulans
- Halimeda stuposa
- Halimeda taenicola
- Halimeda tuna
- Halimeda velasquezii
- Halimeda xishaensis
Individual evidence
- ↑ a b c d e Michael D. Guiry, GM Guiry: Halimeda. In: Algaebase. World-wide electronic publication, National University of Ireland, Galway, accessed June 17, 2013.
- ↑ a b c Wolfram Braune: Marine algae. A color guide to the common benthic green, brown and red algae of the world's oceans . Gantner, Ruggell 2008, ISBN 978-3-906166-69-8 , p. 90.
