- Reference
- Phycol.General. 293 (1843)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus medium to dark red-brown, erect, 10–20(–36) cm high, alternately distichously and complanately branched with prominent main axes and laterals, densely corticated below with entwined rhizoids. Holdfast rhizoidal, conical, 2–15 mm across with 1 to several axes; epilithic. Structure. Apical cells prominent, 130–180 µm in diameter and L/D 1–2, enlarging gradually to 200–300 µm in diameter and L/D 2–4 in lower axial cells, cells with upper concave and lower convex ends, pit-connections prominent and umbonate. Corticating rhizoids produced from basal cells of whorl-branchlets, forming a closely adherent layer, cells long and 25–40 µm diameter, with curved, simple, branches arising from their cells. Whorl-branchlets (pinnae) in opposite pairs (rarely in 3’s) 5–10 mm long, closely branched with opposite, distichous, first simple but soon also pinnate, pinnules 200–500 µm long; basal cells of rachis of pinnae 60–90 µm in diameter and L/D 1–1.5, tapering gradually to subapical cells 12–18 µm in diameter and L/D 1.5–2, with rachides often continuing growth to form an extended filament without pinnules. Whorl-branchlets and pinnules with the basal cell elongate along the pinnule rachis cell, supra-basal cells 15–20 µm in diameter and L/D 1–1.5, tapering gradually, branches thereof 3–6 cells long, cells of similar dimensions, end cell pointed. Lateral branches occur in the position of whorl-branchlets, at irregular intervals and often in pairs. Cells uninucleate; rhodoplasts discoid in smaller cells, in chains in larger cells.
Reproduction. Gametophytes unknown. Tetrasporangia borne on special branch systems on the basal cells of pinnae, terminal, ovoid to subspherical, 40–55 µm in diameter, decussately divided.
Distribution. Cooler and subantarctic waters of the Southern Hemisphere; in southern Australia, from Nuyts Reef, S. Aust., to Green Cape, N.S.W., around Tas., with one record from Geographe Bay, W. Aust.
Habitat. B. callitrichia is one of the commonest species of Rhodophyta on southern Australian coasts, usually in relatively deep water or under an algal canopy.
[After Womersley, Mar. Benthic Fl. Southern Australia IIIC: 149–151 (1998)]