Electronic Flora of South Australia Genus Fact Sheet

Genus CALLOPHYCUS Trevisan 1848: 107

Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Areschougiaceae

Thallus erect, complanately and pinnately branched, branches compressed to flat, with a midrib or not, pinnae basally constricted, margin entire to serrate; holdfast discoid, crustose. Structure multiaxial, with each axial cell producing a single periaxial cell, developing a loose to moderately dense, filamentous medulla of broader longitudinal filaments splaying to the cortex, together with rhizoidal filaments, sharply demarcated from the pseudoparenchymatous cortex.

Reproduction: Sexual plants usually dioecious; non-procarpic. Carpogonial branches 3–4 (–5) -celled, with sterile cells on the lower cells or supporting cell, directed inwards or sideways with a reflexed trichogyne; fertilized carpogonium producing several long connecting filaments. Auxiliary cell an inner cortical cell, with adjacent cells darkly staining, producing first a single gonimoblast initial inwardly, later developing a fusion cell (continuous with the enlarged and fused axial filament) producing gonimoblast filaments radially with chains of carposporangia. Cystocarps with slight filamentous enveloping tissue and a thicker cortex (inner cells radially elongate), buried in and swelling the pinnules, ostiolate. Spermatangia clustered and scattered or restricted to odd cortical cells.

Tetrasporangia scattered in the outer cortex, basally attached, zonately divided.

Life history triphasic with isomorphic gametophytes and tetrasporophytes.

Type species: C. dorsiferus (C. Agardh) Silva 1957: 143.

Taxonomic notes: Four species of Callophycus occur on southern Australian coasts, one of which (C. dorsiferus) together with C. costatus (Harvey) Silva are limited to the west coast of Australia (Min-Thein & Womersley 1976, pp. 14, 19), and three species occur in the Pacific Ocean tropics, with two, C. densus (Sonder) Kraft and C. tridentifer Kraft, found in eastern Australia (Kraft 1984b).

References:

KRAFT, G.T. (1984b). Taxonomic and morphological studies of tropical and subtropical species of Callophycus (Solieriaceae, Rhodophyta). Phycologia 23, 53–71.

MIN-THEIN, U. & WOMERSLEY, H.B.S. (1976). Studies on southern Australian taxa of Solieriaceae, Rhabdoniaceae and Rhodophyllidaceae (Rhodophyta). Aust. J. Bot. 24, 1–166.

SILVA, P.C. (1957). Remarks on algal nomenclature. Taxon 6, 141–145.

TREVISAN, V.B.A. (1848). Saggio di una monografia delle alghe cocotalle. (Padova.)

The Marine Benthic Flora of Southern Australia Part IIIA complete list of references.

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (14 January, 1994)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIA, Bangiophyceae and Florideophyceae (to Gigartinales)
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIA 1994, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

KEY TO SPECIES OF CALLOPHYCUS

1. Thallus branches flat throughout, pinnae 2–4 mm broad, pinnules 1–2 mm broad, closely pinnate but not proliferous

C. dorsiferus

1. Thallus branches compressed to subterete, pinnae 0.5–2 mm broad, closely pinnate and proliferous below or more distantly branched (over 5 mm apart) and less regularly pinnate

2

2. Pinnae and pinnules crowded, proliferous below, subterete to slightly compressed, 0.5–2 mm broad, distinctly slenderer than main branches (2–) 4–5 mm broad

C. oppositifolius

2. Pinnae and pinnules usually over 5 mm apart, distinctly compressed and of similar width to main branches, 1–5 mm broad

3

3. Thallus with usually a single stipe from the discoid holdfast, then dividing into several axes or main branches; axes (2–) 3–5 mm broad, regularly pinnate when young, pinnae and pinnules 1–3 mm broad, some pinnule ends becoming flabellate, apices rounded; cystocarps subterminal in pinnules, protruding on one side

C. harveyanus

3. Thallus with numerous axes from the crustose holdfast; axes 1–1.5 mm broad, irregularly pinnate, pinnae and pinnules 0.5–1 mm broad, apices acute to rounded; cystocarps midway along pinnules and central within the medulla

C. laxus


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