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Electronic Flora of South Australia Family Fact Sheet
Phylum Chlorophyta – Order Caulerpales
Thallus either of tufted, subdichotomous filaments, or of interwoven filaments forming a compressed to complanate, simple or branched thallus differentiated into a medulla and cortex consisting either of filaments similar to the medulla or forming a surface layer of small, inflated "utricles". Heteroplastic, with chloroplasts and amyloplasts, wall containing xylan.
Life history diplontic with meiosis at gametogenesis as far as known; gametangia borne singly or in clusters on cortical filaments or utricles, anisogamous.
Taxonomic notes: Most genera and species of the Udoteaceae are tropical or subtropical, many being calcified (especially Halimeda). Eight genera occur along southern Australia, most with only a single species in this region.
References: The Marine Benthic Flora of Southern Australia Part I
Publication:
Womersley, H.B.S. (31 May, 1984)
The Marine Benthic Flora of Southern Australia
Part I
©Board of the Botanic Gardens and State Herbarium, Government of South Australia
KEY TO GENERA OF UDOTEACEAE
1. Thallus filaments free, simple or branched, forming a loose tuft | 2 |
1. Thallus of slender, interwoven or laterally attached filaments forming a macroscopic thallus, usually compressed | 3 |
2. Thallus under 2 cm high, filaments slender (less than 60 µm in diameter), branched and constricted at their base, simple above | PSEUDOCHLORODESMIS |
2. Thallus usually | CHLORODESMIS |
3. Thallus of flat, discoid or moniliform, calcified segments, joined by narrow, uncalcified nodes | HALIMEDA |
3. Thallus slightly compressed and subdichotomous, or tufted, or complanate and felt-like, simple or branched | 4 |
4. Thallus subdichotomous, branches | PSEUDOCODIUM |
4. Thallus simple or branched, loosely tufted or complanate, usually more than 5 mm broad (Rhipilia may be less broad) | 5 |
5. Thallus much branched, with subdistichous, lateral branch tufts of filaments of elongate, regularly constricted segments with almost complete cross walls; lower axes with dense cortex of moniliform filaments | CALLIPSYGMA |
5. Thallus usually simple, tufted or flabellate to ovate and several filaments thick, spongy | 6 |
6. Thallus to 1.5 cm high and 0.5 cm across, of loose tufts of filaments with occasional tenacula connecting lower filaments | RHIPILIA |
6. Thallus over 2 cm high when mature, compressed, spongy, several filaments thick, with a distinct stipe and lamina; filaments either not connected laterally or connected by circular areas with or without protrusions from the segment | 7 |
7. Thallus (1–) | RHIPILIOPSIS |
7. Thallus | AVRAINVILLEA |
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