Suringariella harveyana (J.Agardh) Womersley & Bailey

Scientific Description

Habit and structure. Thallus dark brown, slightly mucoid, simple or with a few long branches mainly from near the base, rarely proliferous above, 10–25(–50) cm long and 2–6(–14) mm in diameter, cylindrical to slightly flattened in older, hollow and often fistulose plants, with a small discoid holdfast 2–5 mm across, epilithic. Basal system of juvenile plant consisting of radiating, pseudoparenchymatous filaments which produce erect filaments 12–15(–20) µm in diameter and L/B 2–10, with intercalary divisions, and which, by the time they are 0.5 mm long, are partly obscured by abundant hyphae. Medulla of entwined, branched, hyphal filaments 6–10 µm in diameter with cells L/B 4–10, largely obscuring the original longitudinal filaments 16–22 µm in diameter, and producing the peripheral cortical filaments from both the original filaments and the hyphae, without a subcortical region. Cortical filaments determinate, cylindrical, forming a dense, compact cortex of even height (150–350 µm), branched 1–4 times, 8–12(–16) µm in diameter with cells L/B 1–1.5(–2). Phaeoplasts few (3–6) per cell, discoid to irregular in shape, each with a pyrenoid; numerous small physodes usually present in cortical cells. Phaeophycean hairs frequent, arising from inner cortical or outer medullary cells, (10–)12–16 µm in diameter.

Reproduction. Plurilocular sporangia rare, on plants also bearing unilocular sporangia, borne on mid to inner cells of cortical filaments, elongate-ovoid to conical, 80–120 µm long and 20–35 µm in diameter, divided into numerous irregularly positioned locules when mature. Unilocular sporangia usually frequent, borne laterally on inner cortical filaments, ovoid to broadly clavate or obpyriform, 60–120 µm long and (15–)25–50 µm in diameter.

Distribution.From Middle I., Recherche Archipelago, W. Aust., to Walkerville, Vic., and around Tas.

Habitat. Usually on sand covered rock in the lower eulittoral as a summer annual (August to March).

[After Womersley, Mar. Benthic Fl. Southern Australia II: 112 (1987)]