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.
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.
Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
©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.
State Herbarium of South Australia