Electronic Flora of South Australia Genus Fact Sheet
Phylum Phaeophyta – Order Dictyotales – Family Dictyotaceae – Tribe Zonarieae
Thallus largely decumbent to erect, 2–20 cm high, usually with clustered fronds, broadly flabellate to divided and becoming irregularly laterally branched, or subdichotomous, stupose below with a matted, rhizoidal holdfast. Growth by an extensive marginal row of apical cells. Fronds broadest near their flabellate apices, tapering below, usually with faint concentric growth zones. Structure usually 7–9 cells thick, cells in regular rows of uniform size in transverse section except for the distinctly larger central layer (usually one cell thick) of the medulla and the cortical cells which are paired above each medullary cell, with usually four cortical cells corresponding to each medullary cell lengthwise; phaeoplasts dense in cortical cells, less so in medullary cells. Hair tufts phaeophycean, scattered or arranged in concentric lines.
Life history apparently direct from the sporophyte, possibly diplohaplontic and ismorphic.
Reproduction. Sori of sporangia scattered or in concentric groups, on both surfaces,
indusiate and without cellular paraphyses; sporangia producing eight (occasionally four) spores.
Type species: L. nigrescens J. Agardh [ = L. variegata (Lamouroux) Womersley].
Taxonomic notes: A genus of three species, the type and two species still referred to Pocockiella Papenfuss – P. papenfussii Taylor (1950, p. 98) from the Marshall Islands, and P. dichotoma Simons (1966, p. 169) from South Africa; both these species need further investigation.
Lobophora differs from Zonaria in the presence of a central layer of distinctly larger cells in the medulla, and from most species in the absence of cellular paraphyses in the sporangial sori. One species of Zonaria (Z. angustata) also lacks cellular paraphyses, but in form and structure is a typical Zonaria.
AGARDH, J.G. (1894a). Analecta Algologica. Cont. I. Acta Univ. lund. 29, 1–144, Plates 1, 2.
SIMONS, R.H. (1966). A new species of the Dictyotales from South Africa. Bothalia 9, 169–171.
TAYLOR, W.R. (1950). Plants of Bikini and other Northern Marshall Islands. (Univ. Mich. Press: Ann Arbor.)
The Marine Benthic Flora of Southern Australia Part II complete list of references.
Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
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State Herbarium of South Australia