- Reference
- Mar.Benth.Fl.S.Australia 476-478; fig 218 (1998)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus medium to dark red to grey-red, 5–30 cm high, profusely branched with several axes and main branches bearing lesser branches with slender lateral pseudolateral tufts, becoming denuded below. Attachment probably by tufts of rhizoids; epiphytic on Amphibolis, Posidonia, Sargassum and other algae. Structure. Apices sympodial. Pericentral cells 5, remaining clear in transverse section and without surrounding rhizoids. Lesser branches (50–)100–300 µm in diameter with segments L/D 0.8–1.2, becoming corticate from 10–20 segments below apices, cortication complete below and 2–5 cells thick where axes are 500–1000 µm in diameter with segments L/D 0.5–1. Pseudolaterals mostly 2 axial cells apart, 1–2 mm long with 2–5(–7) lower subdichotomies usually 2 cells apart, with adherent joint lower walls and unbranched ends 6–12 cells long; basal cell short, lower cells 35–90(–110) µm in diameter and L/D 2–7, tapering markedly but evenly to upper cells 8–12 µm in diameter and L/D 6–15. Lateral branches arising from basal cells of pseudolaterals. Rhodoplasts discoid to elongate, becoming chained in larger cells.
Reproduction. Gametophytes dioecious. Procarps not observed. Young carposporophytes with cells at base darkly staining, carposporophytes much branched, with a basal fusion cell, carposporangia in rows, ovoid, 12–20 µm in diameter. Cystocarps ovoid, 0.4–1.2 mm in diameter with a slight neck, sessile on short lateral branches with the pericarp often enclosing the continuing branch. Pericarp with 12–14 erect filaments, the cells cutting off outwardly irregularly shaped cells and occasional smaller corticating cells. Spermatangial branches borne as branches of pseudolaterals, sessile, 90–140 µm long and 30–45 µm in diameter, with 1–3 sterile apical cells. Tetrasporangial stichidia borne on lower cells of pseudolaterals, sessile, lanceoid, (100–)200–500 µm long and (50–)90–140 µm in diameter, with 5–12 fertile segments each with 4 tetrasporangia, subspherical and 25–35 µm in diameter and 2 ovoid to obloid cover cells.
Distribution. Hopetoun, W. Aust., to Western Port, Vic., and Flinders I., Bass Strait, and N and E Tas.
Habitat. D. hookeri occurs in relatively sheltered waters.
[After Parsons & Womersley in Womersley, Mar. Benthic Fl. Southern Australia IIIC: 476–478 (1998)]