Sarcotrichia tenera (Harv.) Womersley & Shepley

Scientific Description

Habit and structure. Thallus greyish-red to red-brown, mucilaginous and rapidly disintegrating when detached, usually 10–30 cm high with stout but soft, branched, axes 1–2(–3) mm in diameter and much branched, villose, upper parts bearing monosiphonous filaments. Holdfast small, rhizoidal; epiphytic. Structure. Apical cells dome shaped with axial cells cutting off 4 pericentral cells, the abaxial first followed by 2 lateral cells and lastly the adaxial cell, with the lateral cells each cutting off 2 flanking cells. Monosiphonous filaments, up to 25 cells long, arise from the anterior flanking cells and also from the transverse pericentral cells, thus forming 4 rows along the branches; filaments 16–28 µm in diameter, mid cells L/D 2–3(–4), simple or occasionally becoming branched, caducous some distance below branch apices. Cortication commencing 15–20 segments from apices, becoming heavy on lower terete axes. Lateral branches endogenous. Cells uni- or binucleate in filaments, multinucleate in larger pericentral cells; rhodoplasts discoid, becoming chained.

Reproduction. Gametophytes dioecious. Procarps near the tip of laterals with the adaxial pericentral cell cutting off a first sterile cell, then the initial of the carpogonial branch, then a second sterile cell lying over the carpogonial branch. Carposporophyte with an erect fusion cell and branched gonimoblast filaments bearing clavate to ellipsoid terminal carposporangia 25–40 µm in diameter. Cystocarps ovoid, (500–)800–1000 µm in diameter, sessile on branchlets which form a short stalk; pericarp ostiolate, with about 20 erect filaments, each cell cutting off 2 transversely elongate outer cells. Spermatangial blades clustered on main branches, 400–700 µm long and 80–140 µm broad, with a terminal awn and sterile marginal and transverse pericentral cells, with the lateral pericentral cells producing a layer of initials cutting off outer spermatangia. Tetrasporangial stichidia 500–1500 µm long and 150–200 µm broad, produced from the adaxial surface of mature corticated branches, with the lateral pericentral cells each cutting off a tetrasporangium and abaxial and adaxial cover cells, the sporangia protected also by curved flanking cell derivatives; tetrasporangia 35–55 µm in diameter; slight cortication may occur on older stichidia.

Distribution. Fremantle, W. Aust., to Western Port, Vic., and the N coast of Tas.

[After Womersley, Mar. Benthic Fl. Southern Australia IIID: 155–157 (2003)]