Notheia anomala Harv. & Bailey

Scientific Description

Habit and structure. Thallus dark brown, hemi-parasitic on Hormosira (or Xiphophora chondrophylla) and attached usually adjacent to a host conceptacle, usually 5–12(–20) cm long, much branched, with one to a few simple to occasionally (truly) branched axes bearing numerous irregularly placed laterals arising largely from within conceptacles, or adjacent to them, and probably consisting of new plants, with the whole thallus thus a multiple plant. Main axes 1–2 mm in diameter below, 0.5–1 mm in diameter above, lateral branches 0.3–0.8 mm in diameter, basally constricted within the ostiole and broadening suddenly outside it, linear or tapering slightly to broadly pointed apices, with prominent tufts of colourless phaeophycean hairs 0.5–1 mm long issuing from the ostioles. Growth from a protruding group of 3 apical cells segmenting latero-posteriorly to form elongate cells of medullary filaments and a cortex of shorter cells; tissues from each of the 3 apical cells separated by mucilage and recognisable for 15–20 cells below, then indistinguishable. Outer cortical cells forming a meristoderm, the cells dividing by oblique longitudinal walls and then transversely. Structure largely haplostichous, with occasional intercalary longitudinal cell divisions, differentiating into a medulla of longitudinal filaments 20–40 µm in diameter, and hyphae, with pit-connections linking the cells, and a cortex of filaments of pitconnected cells 15–25 µm in diameter (larger in inner cortex), and L/B mostly 1–1.5, with an outer meristoderm; outer cells with several discoid phaeoplasts, without pyrenoids, with numerous physodes. Phaeophycean hairs with a long basal cell and a meristem, 8–12 µm in diam.

Reproduction. Conceptacles profuse, scattered over the branches, ostiolate, 120–200 µm in diameter, containing colourless, simple, hairs of two thicknesses (the broader phaeophycean) and sessile gametangia. Female gametangia elongate-ovoid, 45–80 µm long and 12–30 µm in diameter, producing 8 pyriform female gametes through basal, lateral or terminal pores, containing 2–4 phaeoplasts and an eyespot, 12–27 µm long and 5–12 µm in diameter.Antheridia 40–80 µm long and 10–25 µm in diameter, producing 64 sperms, with one pale phaeoplast and an eyespot, 6–10 µm long and 4–6 µm in diameter. Female gametes settling on parent tissue before fertilisation, or germinating without fertilisation to form branched filaments bearing erect phaeophycean hairs and erect, uniseriate, reproductive bodies.

Distribution.From Albany, W. Aust., to Port Stephens, N.S.W. and around Tas.

Habitat. N. anomala is usually present and often prolific on Hormosira banksii on rough-water coasts, on rock platforms or around rock pools in the lower eulittoral or just sublittoral.

[After Womersley, Mar. Benthic Fl. Southern Australia II: 336–338 (1987)]