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Ptilothamnion subsimplex Gordon 1972: 129, fig. 42A–F.

Phylum Rhodophyta – Order Ceramiales – Family Ceramiaceae – Tribe Spermothamnieae

Selected citations: Jaasund 1976: 117, fig. 236; 1977: 408. Silva et al. 1996: 423. Wollaston 1984: 293.

Thallus 1–2 mm high, with prostrate filaments bearing sparingly branched erect filaments (Fig. 102G). Attachment by digitate haptera; epiphytic on Lenormandia. Structure. Prostrate filaments 25–35 µm in diameter, cells L/D 2–3.5, erect filaments 30–60 µm in diameter and cells L/D 1–3.5, terminal cell obtuse. Cells multinucleate; rhodoplasts discoid.

Reproduction: Gametophytes monoecious or dioecious. Female axes (Fig. 102H) terminating erect filaments, the last 2 cells short, the hypogenous cell larger and bearing 2 lateral branchlets of 1–2 cells before fertilization. Procarps (Fig. 102H) on the subapical cell, with 2 sterile periaxial cells and the supporting cell with a terminal sterile cell and a lateral carpogonial branch with the third and fourth cells larger. Post-fertilization the cells of the carpogonial branch fuse, but only slight further fusion occurs. The auxiliary cell cuts off 2–5 gonimoblast initials which divide to form carposporangia 30–35 µm in diameter, in gonimolobes (Fig. 102I) which mature simultaneously. Sterile procarp cells do not divide, but the involucral branchlets (Fig. 102I) on the hypogenous cell branch and completely encircle the mature carposporophyte. Spermatangial heads (Fig. 102J) are lateral and sessile on upper cells of the erect filaments, ovoid, 30–40 µm in diameter.

Tetrasporangia (Fig. 102K) are sessile on upper cells of erect filaments, often unilateral, ovoid, 50–65 µm in diameter, tetrahedrally (sometimes appearing decussately) divided.

Type from Pennington Bay, Kangaroo I., S. Aust., on Lenormandia in sublittoral pools (Womersley, 30.i.1946); holotype in AD, A32150.

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

Distribution: Only known in southern Australia from the type.

Recorded from Tanzania by Jaasund (1976, p. 117; 1977, p. 408), from Kenya by Wollaston (1984, p. 293) and from India by Subramanian (1985, p. 72).


GORDON, E.M. (1972). Comparative morphology and taxonomy of the Wrangelieae, Sphondylothamnieae and Spermothamnieae (Ceramiaceae, Rhodophyta). Aust. J. Bot. suppl. 4, 1–180.

JAASUND, E. (1976). Intertidal Seaweeds in Tanzania. (Univ. Troms0.)

JAASUND, E. (1977) Marine algae in Tanzania VI. Bot. Mar. 20, 405–414.

SILVA, P.C., BASSON, P.W. & MOE, R.L. (1996). Catalogue of the Benthic Marine Algae of the Indian Ocean. (University of California Press: Berkeley, Los Angeles & London.)

SUBRAMANIAN, B. (1985). An annotated list of ceramiaceous algae (Rhodophyta) of Tiruchendur coast, South India. Seaweed Res. Util. 7, 71–83.

WOLLASTON, E.M. (1984). Species of Ceramiaceae (Rhodophyta) recorded from the International Indian Ocean Expedition, 1962. Phycologia 23, 281–299.

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

Author: H.B.S. Womersley

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. 102 G–K.

Figure 102 image

Figure 102   enlarge

Fig. 102. A–F. Ptilothamnion schmitzii (AD, A31347). A. Prostrate and erect filaments. B. Mature procarp system. C. Carposporophyte, with 2 involucral branches from the hypogenous cell. D. Monoecious thallus with spermatangial heads and procarp system. E. Longitudinal section of a spermatangial head. F. Prostrate and erect axes with tetrasporangia. G–K. Ptilothamnion subsimplex (AD, A32150). G. Prostrate and erect axes, with spermatangial heads. H. Mature procarp system. I. Mature carposporophyte with involucral filaments from hypogenous cell. J. Longitudinal section of spermatangial head. K. Erect axis with tetrasporangia. (All as in Gordon 1972, courtesy of Aust. J. Bot.)

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