Electronic Flora of South Australia Genus Fact Sheet

Genus MESOGLOIOPSIS Womersley & Bailey gen. nov.

Phylum Phaeophyta – Order Chordariales – Family Chordariaceae

Thallus much and irregularly branched with short, stout laterals, soft and very mucoid, 5–10 cm long and (1–) 2–4 mm in diameter. Medulla multiaxial, of numerous longitudinally orientated slender hyphal filaments well separated from each others, produced from an outer medulla of larger, branched, radially orientated filaments; occasional anastomoses occurring in the outer medulla to produce a partial reticulum. Subcortex absent. Cortex of determinate assimilatory filaments arising in groups from the outer medullary cells, usually slightly curved above. Phaeophycean hairs present, arising from outer medullary cells at base of cortical filaments.

Reproduction: Reproduction by ovoid unilocular sporangia borne on outer medullary cells at base of cortical filaments. Plurilocular sporangia unknown.

Life history unknown.

Type species: M. tasmanica Womersley & Bailey.

Taxonomic notes: Mesogloiopsis lacks a medullary core of laterally associated filaments as found in most genera of Chordariaceae. The outer part of the medulla consists of branched filaments of cells derived from the several more or less longitudinal filaments in each branch apex, but while these remain in the outer medulla and can be traced to the inner medulla, extensive development of hyphae results in the medullary core of numerous, more or less longitudinal but not laterally associated filaments. The thallus thus lacks a clear subcortical zone between the medullary core and the cortex, and the cortex is supported on the original subapical branching filaments which are considered to constitute an outer medullary region. Anastomoses between hyphae and outer medullary cells occur, producing a slight reticulum in this region.

Mesogloiopsis differs from Suringariella in the longitudinal orientation of the medullary hyphae and in having unbranched cortical filaments.

References: The Marine Benthic Flora of Southern Australia Part II

Author: H.B.S. Womersley & A. Bailey

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