Electronic Flora of South Australia Species Fact Sheet

Pterothamnion manifestum (Wollaston) Athanasiadis & Kraft 1994: 130.

Phylum Rhodophyta – Order Ceramiales – Family Ceramiaceae – Tribe Pterothamnieae

Selected citations: Athanasiadis 1996: 68, fig. 22.

Synonym

Glandothamnus manifestus Wollaston 1981: 117, figs 19–30, 42.

Thallus (Fig. 58D) red-brown, erect, 4–10 cm high, complanately branched with alternate lateral branches usually every 2–3 axial cells, ecorticate throughout. Attachment by rhizoids (Fig. 64F) from basal axial cells; epiphytic. Structure. Apical cells 6–8 µm in diameter and L/D 1–1.5, with straight to slightly flexuous apices first developing whorl-branchlets unilaterally, enlarging to 150–300 µm in diameter and L/D 1.5–3 in lower axial cells. Axial cells each with 4 whorl-branchlets (Fig. 63A, B) of similar size, 450–750 µm long, each at first adaxially branched but becoming subdichotomous (Fig. 64D); basal cells of whorl-branchlets 20–40 µm in diameter and L/D 1.5–3, tapering to 7–12 µm in diameter and L/D 1.5–2.5 in subapical cells, terminal cells mucronate; gland cells (Fig. 64D, E) prominent, abundant (often on 2–4 successive cells), sessile, ovoid becoming oblique, 18–22 µm in diameter. Lateral branches arising from axial cells or on the basal or next cell of whorl-branchlets. Cells uninucleate; rhodoplasts discoid to elongate in smaller cells, becoming ribbon like and reticulate in larger cells.

Reproduction: Gametophytes dioecious. Carpogonial branches (Fig. 64G) borne on the basal (supporting) cell of whorl-branchlets, often in a short series. Post-fertilization the carpogonium and auxiliary cell connect by a tubular process and the auxiliary cell cuts off a rounded gonimoblast initial (Fig. 64H) and successive gonimolobes (Figs 63A, 64I) from elongate basal cells, developing into rounded groups 200–400 µm across of ovate to angular, carposporangia 10–18 µm in diameter. Spermatangial clusters (Figs 63B, 64J) occur on inner and central cells of whorl-branchlets, with terminal and lateral spermatangia.

Tetrasporangia unknown.

Type from Satellite I., D'Entrecasteaux Ch., Tas., 0–2 m deep, probably epiphytic (Shepherd, 17.ii.1972); holotype in AD, A41641.

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

Distribution: Known from the type and Satellite I., Tas., 10 m deep (Shepherd, 18.ii. 1972; AD, A41699) and from Arch Rock, Ninepin Point, Tas., on Zonaria turneriana, 6–12 m deep (Kraft 9837 & Scott, 16.i.1994; AD, A66645).

References:

ATHANASIADIS, A. & KRAFT, G.T. (1994). Description of Pterothamnion squarrulosum (Harvey) comb. nov. from south-eastern Australia and southern New Zealand, with a taxonomic re-assessment of the genera Pterothamnion, Platythamnion & Glandothamnus (Ceramiaceae, Rhodophyta). Eur. J. Phycol. 29, 119–133.

ATHANASIADIS, A. (1996). Morphology and classification of the Ceramioideae (Rhodophyta) based on phylogenetic principles. Opera Botanica No. 128, pp. 1–216.

WOLLASTON, E.M. (1981). Descriptions of two new genera, Scageliopsis and Glandothamnus (Ceramiaceae, Rhodophyta), including five previously undescribed species from southern Australia. Pacific Sci. 34, 109–127.

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

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

Illustrations in Womersley Part IIIA, 1998: FIGS 58D, 63A, B, 64 D–J.

Figure 58   enlarge

Fig. 58. A. Pterothamnion nodiferum (AD, A31499). B. Pterothamnion squarrulosum (AD, A48820). C. Pterothamnion ramulentum (MEL, 10258). D. Pterothamnion manifestum (AD, A41641). E. Pterothamnion flexile (AD, A46637). Habit of each species.

Figure 63   enlarge

Fig. 63. A, B. Pterothamnion manifestum (AD, A41641). A. Branches with gland cells on pinnules, and two carposporophytes. B. Male thallus with spermatangial clusters. C–E. Pterothamnion ramulentum (C, E, AD, A41084; D, AD, A30874). C. Carposporophyte. D. Spermatangial clusters on cells of pinnae, with gland cells. E. Branches with tetrasporangia.

Figure 64   enlarge

Fig. 64. A–C. Pterothamnion aciculare (AD, A46154). A. Apical development. B. Immature whorl-branchlets with a terminal spinous process and continued development from the cell below the process. C. Whorl-branchlet with gland cells and tetrasporangia. D–J. Pterothamnion manifestum (AD, A41641). D. Mature subdichotomous whorl-branchlet with gland cells. E. Development of a gland cell. F. Rhizoids bearing gland cells. G. Apex of a lateral branch with carpogonial branches on basal cells of whorl-branchlets. H. Young carposporophyte with gonimoblast initials. I. Older carposporophyte with lateral gonimoblast initials. J. Spermatangial clusters. (All as in Wollaston 1981, courtesy of Pacific Science, Uni. of Hawai'i Press.)

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