Electronic Flora of South Australia Family Fact Sheet


Phylum Phaeophyta

Thallus slightly compressed to flattened, erect or prostrate, usually 2–30 cm long, with irregular narrow branches to flabellate, with apical hair tufts or a margin of hairs when flabellate, and in cross section with a small-celled cortex and a medulla of irregularly placed rounded cells. Growth trichothallic, at the base of the tufts of hairs with a polystichous thallus developing below. Phaeoplasts numerous in each cell, discoid, some with a small pyrenoid. Phaeophycean hairs scattered, single or in small clusters.

Reproduction: Gametophytes dioecious or monoecious, anisogamous, bearing pedicellate gametangia in clusters on simple or branched uniseriate filaments, with some filaments extending as phaeophycean hairs; female gametangia with 8–16 larger locules, male gametangia on more branched filaments with numerous smaller locules. Sporophytes with surface sori of unilocular meiosporangia liberating 8, 16 or 32 motile meiospores.

Life history diplohaplontic, isomorphic (Zanardinia) or heteromorphic (Cutleria), the latter with an erect gametophyte and a prostrate, flabellate sporophyte several cells thick with a marginal meristem.

Taxonomic notes: This is a small order with a single family and three genera. Pyrenoids are inconspicuous (Hori & Ueda 1975, p.30). Only Cutleria is known from sheltered habitats in southern Australia, and then only from the female gametophyte (which may be parthenogenetic) and the sporophyte (Aglaozonia stage) which is known from Port Phillip Bay, Vic.


HORI, T. & UEDA, R. (1975). The fine structure of algal chloroplasts and algal phylogeny. In Tokida, J. & Hirose, H., Advance of Phycology in Japan, pp. 11–42. (Junk: The Hague.)

The Marine Benthic Flora of Southern Australia Part II complete list of references.

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
Part II
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