Peyssonnelia inamoena Pilg.
Bot.Jahrb.Syst. 311 (1911)

Conservation Code: Not threatened
Naturalised Status: Native to Western Australia
Name Status: Current


IMCRA Regions: Abrolhos Islands, Central West Coast, Leeuwin-Naturaliste.

Local Government Areas (LGAs): Broome, Cockburn, Greater Geraldton.

Scientific Description
John Huisman & Cheryl Parker, Thursday 8 September 2016

Habit and structure. Thallus medium to dark red, (0.5–)1–2 cm across, orbicular, incompletely adherent to varying extents, with faint concentric growth zones and radial striae, 70–100 µm thick, epilithic or epiphytic. Structure. Basal layer of essentially parallel filaments, 12–18 µm in diameter from below with cells L/D 1.5–2(–4), 12–16 µm in height and L/D 1–1.5(–2), often rhomboidal in RVS, with many cells producing unicellular rhizoids 8–12 µm in diameter; hypobasal calcification present. Erect filaments 3–6(–12) cells long, at (50–)60–85°, the lowest cell usually more erect but similar (or slightly smaller) in dimensions to the basal layer cell and pit-connected centrally to it, then with two branches (and occasional upper ones), upper cells (8–)10–12 µm in diameter and L/D 0.5–1, arranged in surface view in distinct rows of square to polygonal cells; internal calcification absent.

Reproduction. Female nemathecia superficial, with paraphyses 8–12 cells long, lower and mid cells 4–6 µm in diameter, L/D 2–5; carpogonial and auxiliary cell branches 3–5 cells long; carposporangia in rows of 2–3 on a small gonimoblast cell arising from the fusion cell, more or less isodiametric and 25–35 µm across. Spermatangia unknown. Tetrasporangia in shallow sori among 5–6-celled paraphyses, 45–60 µm long and 18–30 µm in diameter cruciately divided.

Distribution. Widely distributed in tropical to warm temperate seas. In southern Australia, known from the Head of the Great Australian Bight, S. Aust., to D'Entrecasteaux Ch., Tas.

Habitat. P. inamoena occurs in heavily shaded pools to deep water.

[After Womersley, Mar. Benthic Fl. Southern Australia IIIA: 164–165 (1994)]