Codium silvae Womersley

Scientific Description

Habit and structure. Thallus medium green, erect, to 30 cm high, irregularly dichotomously and laterally branched at intervals of one to several cm, branches terete, tapering gradually from 6–8 mm in diameter near the base to 3–5 mm in diameter near the branch apices. Utricles arising singly from medullary filaments, elongate clavate to subterete and often of greatest diameter shortly below the apex, 125–250 µm in diameter when mature and (750–)850–1150 µm long; utricle wall thin near the base, thickening towards the apex and forming a finely lamellate, often galeate, cap 25–40 µm thick, internal spinous trabeculae formed profusely from the galeate cap, occurring with less frequency and smaller size downwards over the upper quarter to one third of the utricle; trabeculae 10–30 µm long, basally 5–20 µm thick, tapering to a point, simple or rarely with a branch, often appearing to have an internal cavity which extends into the utricle wall; hairs probably rare, only a few possible hair-scars observed about one quarter of the length of the utricle from the apex. Medullary filaments 25–50 µm in diameter, with a prominent plug adjacent to the utricle base.

Reproduction. Gametangia borne one third to a half the utricle length from the apex, terete to lanceolate, one or two per utricle, 180–300 µm long by 50–70 µm in diameter.

Distribution. Only known from Eucla, W. Aust.

[After Womersley, Mar. Benthic Fl. Southern Australia I: 234 (1984)]