Chondria lanceolata Harv.

Scientific Description

Habit and structure. Thallus dark red-brown, 2–6 cm high, much branched irregularly radially for 3–4 orders, sometimes slightly distichous, branches terete near apices, compressed in mid and lower branches; lower branches 500–800 µm broad where compressed, grading to lesser branchlets 300–350 µm in diameter, young branchlets basally constricted but this soon lost. Holdfasts discoid, 0.2–0.8 mm across, or with short lateral branches attached by discoid haptera; epiphytic on Posidonia or epilithic. Structure. Apices tapering gradually to an apical filament 8–10 cells long, apical cell dome-shaped, 8–10 µm in diameter, with 5 pericentral cells not readily distinguished from inner cortical cells, cortex 2–3 cells broad, transversely and 5–7 cells laterally, epidermal cells 10–15(–18) µm in diameter and L/D 1–3.5(–6). Cell wall thickenings lenticular to band-like, mainly on the outer and radial walls of the pericentral and inner cortical cells. Cells with discoid rhodoplasts.

Reproduction. Gametophytes dioecious. Procarps several cells up on trichoblasts. Carposporophytes with a basal fusion cell and branched gonimoblast with clavate terminal carposporangia 35–65 µm in diameter. Cystocarps ovoid, 700–1200 µm in diameter, with a short stalk and often a rounded basal protrusion; pericarp ostiolate, with 16–18 erect filaments, ecorticate or lightly corticate below. Spermatangial plates (one seen) discoid, 250–300 µm across, with a sterile margin one cell broad. Tetrasporangia in lesser branchlets, on 1–2 pericentral cells per axial cell, 60–140 µm in diameter.

Distribution.Houtman Abrolhos to Point Peron W. Aust., and probably from Scott Bay, S. Aust.

[After Womersley, Mar. Benthic Fl. Southern Australia IIID: 446–448 (2003)]