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Electronic Flora of South Australia Species Fact Sheet
Phylum Phaeophyta – Order Dictyosiphonales – Family Giraudiaceae
Thallus (Fig. 112A) red-brown, with a prostrate disc (0.2–) 0.5–1.0 mm across and erect axes 0.5–2 mm high, epiphytic on the utricle ends of Codium mamillosum. Basal plate (Fig. 112A,B) fan-like, of closely appressed, subdichotomous filaments of phaeoplastic cells 8–15 µm across and L/B 1–2, with marginal growth. Erect axes (Fig. 112A,B) arising directly from scattered cells of the basal plate, simple or branched, filiform, tapering gradually to, usually, a terminal phaeophycean hair (Fig. 1 12C) 12–20 p.m in diameter, occasionally with a single apical cell; growth mainly subapical; tiers of 2–3 cells (Fig. 112B) for most of the axis length, cells 15–25 µ across and L/B (1–) 1.5–3, with small discoid phaeoplasts each with a small pyrenoid, and abundant physodes. Vegetative reproduction occurs by stolon-like filaments, the end of which adheres and establishes a new basal plate.
Reproduction: Plurilocular sporangia (Fig. 112B,C) terminal or subterminal on erect axes or intercalary and surmounted by a phaeophycean hair, cylindrical or tapering, multiseriate, with the central cells remaining sterile, peripheral loculi becoming irregularly arranged and each with a pore, 50–150 µm long and 20–30 µm in diameter.
Type from Stanley Beach, Kangaroo I., S. Aust., on Codium mamillosum, (Womersley, 6.ii.1957); in ADU, A20906.
Distribution: Kangaroo I., Elliston, and the coast of Fleurieu Peninsula, S. Aust.
References:
SKINNER, S. & WOMERSLEY, H.B.S. (1984). Southern Australian taxa of Giraudiaceae (Dictyosiphonales, Phaeophyta). Phycologia 23, 161–181.
The Marine Benthic Flora of Southern Australia Part II complete list of references.
Publication:
Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
Part II
©Board of the Botanic Gardens and State Herbarium, Government of South Australia
Illustration in Womersley Part II, 1997: FIG. 112.
Figure 112 enlarge
Fig. 112. Flabellonema codii (ADU, A20906, holotype). A. Diagram of thallus on a utricle of Codium mamillosum, with the prostrate disc and erect axes terminating in hairs. B. Part of the prostrate disc (with stolon-like filaments) and erect axes, one cell shown with phaeoplasts, and a lateral plurilocular sporangium. C. Two erect axes showing plurilocular sporangia below apical hairs; sporangium on the left with some empty locules.
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