Electronic Flora of South Australia Species Fact Sheet

Cladophora aegagropiloidea van den Hoek & Womersley sp. nov.

Phylum Chlorophyta – Order Cladophorales – Family Cladophoraceae

Thallus (Fig. 60B) light to medium green, forming free-floating or unattached balls 1–3 cm in diameter with filaments radiating from the central or lower part; filaments densely branched with laterals from every cell except often for the 1–4 (–10) upper (outermost) cells (Fig. 61A). Growth vaguely acropetal to irregular, with mainly apical but also intercalary divisions; angle of branching usually narrow (30–45°), with most cells bearing 1 (-2, rarely 3), laterals; insertion of branches usually slightly to markedly subterminal (especially below) with vertical to steeply inclined basal walls (Fig. 61A) which may be a short distance from the parent cell; older cells often bearing opposite, serially or irregularly arranged laterals; cells with walls somewhat irregular to undulate, not linear, lower cells clavate, often bearing descending rhizoids from their basal poles (Fig. 61B). Apical cells cylindrical with rounded tips. A tendency for inversion of polarity results in the outgrowth of branches from opposite cell poles within one and the same axis (Fig. 61A1).

Apical cells 30–40 (–48) µm in diameter, L/B (4–) 6–15, increasing only slightly to lower cells 30–72 (–112) µ in diameter and L/B 2.5–7; ratio of lower cell to apical cell diameters 1–2 (–3); cell walls relatively thick, 5–15 µ in main filaments.

Reproduction: Reproduction unknown, but the balls increase by fragmentation.

Type from the Bay of Shoals, Kangaroo I., S. Aust., drift (Womersley, 1311950); in ADU, A12607-"Marine Algae of southern Australia" No. 219.

Distribution map based
on current data relating to
specimens held in the
State Herbarium of SA

Distribution: Only known from the type locality.

Taxonomic notes: This species was found on the one occasion, with vast numbers of balls floating or washed ashore in the calm-water, shallow (3–5 m deep) Bay of Shoals on Kangaroo Island. It was not seen attached, but the extensive beds of the sea-grass Posidonia in the bay were not checked for Cladophora on the leaves. The locality has not been visited more recently.

The Bay of Shoals is typically marine with no significant fresh-water input. Cl. aegagropiloidea thus differs in its habitat from the closely related fresh-water Cl. aegagropila (L.) Rabenhorst (see van den Hoek 1963, p. 51) and it is also a slenderer species, especially in the lower filaments.


VAN DEN HOEK, C. (1963). Revision of the European species of Cladophora. (Brill: Leiden.)

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

Author: C. van den Hoek and H.B.S. Womersley.

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

Illustration in Womersley Part I, 1984: FIGS 60B, 61A,B.

Figure 61 image

Figure 61   enlarge

Fig. 61. A,B. Cladophora aegagropiloidea (Type, ADU, Al2607). A. Upper branch system. A'. Part of thallus showing reversion of polarity. B. Lower thallus. C,D. Cladophora coelothrix (ADU, A22470). Branch systems with rhizoids. E–I. Cladophora subsimplex (E–H, ADU, A30024; I, ADU, A52662). E. Branching pattern. F. Upper branch system. G. Apical cell. H. Lower branches with rhizoids. I. Fertile upper branches.

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