Electronic Flora of South Australia Species Fact Sheet
Phylum Phaeophyta – Order Fucales – Family Cystoseiraceae
Thallus (Fig. 143B) dark brown, usually 30–60 cm long, with relatively slender primary (and secondary) axes bearing slender, lax, densely branched, laterals. Holdfast discoid-conical, 3–12 mm across; epilithic. Primary axes compressed, 2–4 mm broad below, 1–2 mm thick, oblong in transverse section, distichously branched at intervals of 3–10 mm with prominent (retroflex near the base) branch residues on lower parts of primary and older secondary axes; all branches from the face of the axes, attached for most of the width of the axis. Laterals (Fig. 145E) 2–6 cm long, lax and slender, alternately distichous, with terete ramuli 5–10 (–15) mm long and 250–500 (–600) µm in diameter, lying largely in the one plane and tapering only slightly from base to apex, with moderately acute axils. Vesicles absent.
Reproduction: Thalli monoecious. Receptacles (Fig. 145E) simple or branched, 2–6 (–8) mm long and 500–700 µm in diameter, terete to slightly compressed, smooth to slightly verrucose but drying moniliform. Conceptacles essentially in two rows, bisexual; oogonia ovoid, sessile, 100–160 µm long and 55–80 µ in diameter; antheridia sessile or on branched paraphyses, elongate-ovoid, 20–25 µm long and 7–10 µm in diameter.
Type from Cape Naturaliste, W. Aust., upper sublittoral (Womersley, Clarke & Engler, 2.ix.1979); in ADU, A50627.
Taxonomic notes: C. tenuis is related to both C. brownii and C. harveyi, differing from the former in having longer, laxer, often slightly displaced ramuli, a less robust primary axis, and receptacles with conceptacles more distinctly in two rows, and from C. harveyi in having slenderer axes with the secondary axes or laterals attached for the full width of the parent branch.
C. tenuis appears to be restricted to south-west Western Australia.
References: The Marine Benthic Flora of Southern Australia Part II
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
Illustrations in Womersley Part II, 1997: FIGS 143B, 145E.
Figure 143 enlarge
Fig. 143. A. Cystophora harveyi (ADU, A50628, holotype). B. Cystophora tenuis (ADU, A50627, holotype).
Figure 145 enlarge
Fig. 145. Receptacles of species of Cystophora. A. Cystophora brownii (ADU, A26713). B,C. Cystophora gracilis (ADU, A26725, holotype). D. Cystophora harveyi (ADU, A50628, holotype). E. Cystophora tenuis (ADU, A50627, holotype). F,G. Cystophora retorta (ADU, A26877). F. Secondary and tertiary axes and laterals. G. Receptacles. H. Cystophora siliquosa (ADU, A2812).
State Herbarium of South Australia