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Electronic Flora of South Australia Species Fact Sheet

Callithamnion propebyssoides Womersley, sp. nov

Phylum Rhodophyta – Order Ceramiales – Family Ceramiaceae – Tribe Callithamnieae

Thallus (Fig. 117A) 1–2 cm high, medium red-brown, erect and tufted with indeterminate axes bearing radially shorter lateral branches themselves with spirally arranged determinate branchlets (Fig. 117B), ecorticate except possible slight rhizoidal cortication near the base of axes. Attachment by rhizoids from basal cells of erect axes; epiphytic (on Caulocystis). Structure. Apices of axes inconspicuous, apical cells of branches 6–9 µm in diameter and L/D 1–1.5 (–2), subapical cells gradually increasing to 10–15 µm in diameter and L/D 1–1.5 in subspherical to ovoid cells and lower branchlet cells, then to 40–60 µm in diameter and L/D 2–3 in mid axial cells (Fig. 117B, C), with lower cells 80–120 µm in diameter and L/D (1–) 3–4. Determinate branchlets 200–400 µm and 5–10 cells long, with 2–3 orders of branches , apical cells 7–10 µm in diameter and L/D 1–2. Lateral indeterminate branches developing from determinate branchlets. Cells uninucleate; rhodoplasts discoid to elongate in smaller cells, ribbon like in larger cells.

Reproduction: Gametophytes dioecious. Procarps borne on mid cells of upper axes or main branches, with 2 periaxial cells, one bearing a 4-celled carpogonial branch; post-fertilization each periaxial cell cuts off an auxiliary cell which develops a branched carposporophyte (Fig. 117C, D) with deep pyramidal lobes of carposporangia 10–15 µm across; no involucral filaments occur. Spermatangia on small branched clusters on upper cells of determinate branchlets.

Tetrasporangia (Fig. 117E) sessile on cells of branchlets, subspherical, 30–40 µm in diameter, decussately to tetrahedrally divided.

Type from Fisherman Bay, Port Broughton, S. Aust., on Caulocystis (uvifera ?), drift (Womersley, 23.viii.1967); holotype and isotype in AD, A31803.

Distribution map based
on current data relating to
specimens held in the
State Herbarium of SA

Distribution only known from the type.

Taxonomic notes: C. pseudobyssoides differs from C. byssoides in habit, having shorter, more distinct, determinate branchlets with broader and shorter subapical and lower axial cells. Reproductively however they are similar.

The specific epithet refers to the similarity with C. byssoides.

References: The Marine Benthic Flora of Southern Australia Part IIIC

Author: H.B.S. Womersley & E.M. Wollaston

Publication: Womersley, H.B.S. (24 December, 1998)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIC. Ceramiales – Ceramiaceae, Dasyaceae
©State Herbarium of South Australia, Government of South Australia

Illustration in Womersley Part IIIA, 1998: FIG. 117.

Figure 117 image

Figure 117   enlarge

Fig. 117. Callithamnion propebyssoides (AD, A31803). A. Habit on Caulocystis uvifera. B. Branches with lateral branchlets. C. Branches with branched carposporophytes. D. Twinned, branched carposporophytes. E. Branches with tetrasporangia.

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