Bellotia eriophorum Harv.

Scientific Description

Habit and structure. Thallus medium to dark brown or green-brown, 5–20(–25) cm long, with one to a few simple axes 3–8(–15) cm long, becoming branched from their apices with clusters of 5–30 further branches, each 3–15 cm long, occasionally similarly branched again, all branches with prominent apical tufts of assimilatory filaments; attachment by a rhizoidal holdfast 2–6 mm across and 1–4 mm long; epilithic. Growth apical, with a broad, convex, branch meristem surmounted by the dense tuft of trichothallic filaments (0.5–)1–2.5 cm long, each with a meristem 14–20 cells above their base, 50–65 µm in diameter above with cells L/B 2–3. Fronds (branches) fairly robust, 0.5–1 mm in diameter when sterile, usually tapering slightly to their base. Structure haplostichous and pseudoparenchymatous, with a broad medulla of elongate cells and a multilayered cortex, increasing by periclinal divisions, with the surface cells 6–8 µm across and L/B 1–2.

Reproduction. Sporangial sori surrounding the branches almost anywhere along their length, 1–7 cm long and (0.8–)1–2 mm in diameter, usually (but not always) with a sterile region 2–30 mm long below the apical tuft and at the branch base. Paraphyses compact, simple, 220–250 µm and 10–12 cells long, slightly clavate with the upper 4–5 cells slightly larger, the apical cell rounded to conical, 10–17 µm in diameter and L/B(1–)1.2–1.6,with the subapical cell often slightly broader than the apical cell. Unilocular sporangia borne laterally on the lower cells of the paraphyses, 20–25 µm long and 7–9 µm in diameter, often with a basal, spherical, vesicle within the sporangium.

Gametophyte unknown.

Distribution.From Hasler I., W. Aust., to Walkerville, Vic., and around Tas. Qld. (Noosa Hds, Alexandra Hds).

Habitat. B. eriophorum is a deep water plant on rough-water coasts or in areas of moderate currents.

[After Womersley, Mar. Benthic Fl. Southern Australia II: 286–289 (1987)]