Electronic Flora of South Australia Family Fact Sheet

FAMILY DERBESIACEAE Hauck

Phylum Chlorophyta – Order Derbesiales

Thallus diplohaplontic, heteromorphic, with filamentous sporophyte and ovoid, vesiculate gametophyte, or diplontic with a filamentous sporophyte only. Sporophyte of coenocytic, branched filaments, usually with a double septum at the base of occasional branches; gametophyte ("Halicystis" stage) coenocytic, ovoid, usually 5–10 mm high, attached within the surface of crustose coralline algae by basal rhizoids; chloroplasts lenticular, with or without a pyrenoid.

Reproduction: Reproduction of the sporophyte by ovoid to globular sporangia cut off by a wall plug and borne laterally on the filaments, producing _multi-flagellate (stephanokontic) zoospores; the gametophyte by biflagellate anisogametes formed in areas of protoplasm separated by a membrane.

References: The Marine Benthic Flora of Southern Australia Part I

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (31 May, 1984)
The Marine Benthic Flora of Southern Australia
Part I
©Board of the Botanic Gardens and State Herbarium, Government of South Australia

KEY TO GENERA OF DERBESIACEAE

1. Thallus heteromorphic, with slender, branched sporophyte (less than 100 µm in diameter) and ovoid, vesiculate gametophyte

DERBESIA

1. Thallus sporophytic only, with erect, unbranched, clavate filaments (1–3 mm in diameter) arising from finer filaments and a prostrate base with calcified cell walls

PEDOBESIA


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