Electronic Flora of South Australia Species Fact Sheet

Cladophora hutchinsioides van den Hoek & Womersley sp. nov.

Phylum Chlorophyta – Order Cladophorales – Family Cladophoraceae

Thallus (Fig. 66A) medium to dark green, 5–20 cm high, erect, not tufted, loosely to moderately densely branched, more or less flabellate when young, composed of strands of coarse, branched filaments when older, arising from a small basal disc developing radiating rhizoids (Fig. 67C), growing on solid substrates; filaments fairly uniform in diameter to the upper, tapering branchlets, branched largely adaxially (Fig. 67A, B) every few cells above but with long rows of short unbranched cells below (Fig. 67D) and often ending in long unbranched rows of swollen zooidangia. Growth very largely intercalary, with apical and subapical cell divisions above and when young distinctly acropetal; laterals becoming separated by few to many cells when older, composed of coarse pseudodichotomous main filaments bearing unilateral rows of branchlets mainly above, and mostly conspicuously bare below; parent cells bearing normally only one lateral (occasionally 2) at an angle of about 45°; basal cross walls of laterals oblique, later becoming almost horizontal below.

Apical cells (Fig. 67A,B) usually markedly tapering with obtuse tips, 60–120 in basal diameter and L/B 1.5–3; ultimate branch cells 70–180 in diameter, L/B 1–4; lower thallus cells 200–300 µ in maximum diameter, L/B 1–5; ratio of lower cell to apical cell diameters 2.5–3.5; cell walls relatively thin above (2–4 (–6) µm), thick and lamellate below (up to 20 (–30) µm).

Reproduction: Reproduction by terminal chains of cells becoming slightly swollen zooidangia (Fig. 67D).

Type: Type locality: Port Adelaide, S. Aust. 0.3–1 m below water level on old barge at Harbours Board Wharf. ( Womersley, 25.xi.1957).

Holotype: ADU, A21325.


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

Distribution: Apart from the type, known from Topgallant I., off W. coast of Eyre Pen., S. Aust., 20–25 m deep (Shepherd, 8.xi.1980; ADU, A51880). North Arm, Port Adelaide, S. Aust., 0.3–0.5 m deep on Commercial Fishing Marina (Womersley & van den Hoek, 1.x.1981; ADU, A52644 and Womersley, 10.iii.1982; ADU, A52980). Port Phillip, Vic. 0–0.5 m deep at Power Station outfall (Watson, 1.v.1972; ADU, A42340).

Taxonomic notes: This species is similar in morphology and habit to the European Cl. hutchinsiae (Dillwyn) Kützing (see van den Hoek 1963: 60, figs 131–145) but differs in its smaller dimensions. However, the type of Cl. daviesii Harvey (1855b, p. 263) from New Zealand (herb. Harvey, TCD) does belong to the form range of European Cl. hutchinsiae, and has similar dimensions.

References:

HARVEY, W.H. (1855b). Algae. In J.D. Hooker, The Botany of the Antarctic Voyage. Part II. Flora Novae-Zelandiae. Vol. 2, pp. 211–266, Plates 107–121.

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


Illustrations in Womersley Part I, 1984: FIGS 66A, 67 A–D.

Figure 66 image

Figure 66   enlarge

Fig. 66. A. Cladophora hutchinsioides (Holotype). B. Cladophora montagneana (ADU, A51018). C. Cladophora albida (ADU, A52682). D. Cladophora crinalis (ADU, A52690).

Figure 67 image

Figure 67   enlarge

Fig. 67. A–D. Cladophora hutchinsioides (ADU, A21325). A,B. Upper branch systems. C. Basal cell with attachment rhizoids. D. Upper branches with zooidangia. E–I. Cladophora montagneana (E,F ADU, A51018; G–I, ADU, A19900). El,E2,F. Upper filaments showing branching. G,H. Filaments from upper thallus. I. Apical cells.


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