Caloglossa leprieurii (Mont.) G.Martens

Scientific Description

Habit and structure. Thallus red-brown, forming loose entangled mats 5–20 mm thick, composed of arching, flat, linear, monopodial main branches attached at the constricted nodes by uniseriate rhizoids which become clumped and form basal stipes up to 4 mm high and 400–800 µm in diameter, base of stipe discoid, bearing apically clusters of branched fronds 10–20 mm long, branches (0.5–)1–2(–3) mm broad, linear with internodes usually 2–8 mm long separated by nodal constrictions; epiphytic on mangroves or epilithic, usually lower to mid eulittoral. Structure. Growth apical, with a dome-shaped apical cell and the axial cells cutting off first 2 lateral pericentral cells, then ventral and dorsal pericentral cells, the lateral pericentral cells each developing a second-order cell row which produces abaxially third-order rows 10–20 cells long and which reach the blade margin and sometimes cut off fourth-order cells; secondary pit-connections numerous. Blades monostromatic apart from the central midrib, ecorticate, margins entire, more-or-less flat. Branching of main blades exogenous near apices with adventitious proliferations arising mainly from nodal pericentral cells. Cells mostly multinucleate; rhodoplasts discoid to elongate.

Reproduction. Gametophytes dioecious. Procarps borne in series on dorsal pericentral (supporting) cells, with usually a single cystocarp developing per branch. Fusion cell branched and incorporating lower gonimoblast cells, carposporophyte much branched with short chains of ovoid to angular carposporangia 20–28 µm across. Cystocarps ovoid, ostiolate, 500–750 µm in diameter; pericarp with 8–10 erect filaments, each cell cutting off outer pericentral cells and cortical cells near the base, with the outer pericarp cells becoming irregular in shape and position. Spermatangial sori on both sides of blades apart from over and near the mid-rib and along the margins, with the primary cells cutting off several initials which each produce several spermatangia. Tetrasporangia formed in sori near branch tips, cut off from second- and third-order cells and lying in regular rows, with the stalk cell then cutting off a cover cell on each surface, cover cells becoming irregularly lobed; tetrasporangia subspherical, 30–45 µm in diameter.

Distribution. Widespread in tropical to cool temperate oceans. In southern Australia, from Wallaroo eastwards, on Avicennia trunks and pneumatophores, and on rock and jetty piles, in calm localities through Vic., N and E Tas., and around N Aust.; extending upstream in fresh-water in some localities.

[After Womersley, Mar. Benthic Fl. Southern Australia IIID: 23–25 (2003)]