Electronic Flora of South Australia Species Fact Sheet

Hecatonema maculans (Collins) Sauvageau 1897: 248, figs 18–22.

Phylum Phaeophyta – Order Dictyosiphonales – Family Punctariaceae

Selected citations: Cardinal 1964: 76, fig. 40. Clayton 1974: 790, figs 27–29. Kuckuck 1953: 319, figs 1–3.

Synonym

Phycocelis maculans Collins 1896: 459, pl. 278.

Thallus (Fig. 115A) brown, 0.5–2 mm high and across, with a basal disc of loosely to compactly arranged radiating, branched, filaments, 10–15 µ in diameter with cells L/B 1–2, with occasional to frequent intercalary longitudinal divisions. Erect filaments (Fig. 115A) simple or usually irregularly branched, 12–18 µm in diameter with cells L/B 1–1.5 (–2.5), with occasional intercalary longitudinal divisions; phaeophycean hairs terminal or lateral, with a basal sheath, 10–16 µm in diameter; cells (Fig. 115B) with several discoid phaeoplasts, each with a pyrenoid. Growth of disc filaments apical, of erect filaments intercalary.

Reproduction: Plurilocular sporangia (Fig. 115A) frequent, multiseriate, sessile or pedicellate on basal disc cells or more frequently on erect filaments, lanceolate and tapering to a narrow, often uniseriate apex, occasionally branched or with short outgrowths, 60–110 (–125) µm long and 20–32 µm in diameter, with the zooids reproducing the filamentous thallus directly or the latter becoming parenchymatous and Punctaria or Desmotrichum-like (Clayton 1974, p. 793).

Type from Spectacle I., Penobscot Bay, Maine, U.S.A., in a shallow pool on Rhodymenia palmata; in NY?


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

Distribution: Widely distributed in temperate seas.

In southern Australia known from Apollo Bay, Vic., on Asperococcus bullosus on Heterozostera in lower eulittoral pools ( Womersley, 13.x.1985; ADU, A56893); Point Lonsdale, Vic., on Xiphophora chondrophylla (Clayton, 1.iv.1971; MELU, 20849; ADU, A43054); Flinders, Vic. (Clayton, 18.i.1971; MELU, 21058); and probably Woodbridge, Tas., on Ecklonia, upper sublittoral (Skinner, 24.ii.1978; ADU, A49186). Clayton (1974, p. 790) records H. maculans as epiphytic on several green, brown and red algae.

Taxonomic notes: Hecatonema maculans is probably more widespread on southern Australian coasts than the above records indicate.

References:

CARDINAL, A. (1964). Étude sur les Ectocarpacees de la Manche. Nova Hedwigia 15, 1–86, Figs. 1–41.

CLAYTON, M.N. (1974). Studies on the development, life history and taxonomy of the Ectocarpales (Phaeophyta) in southern Australia. Aust. J. Bot. 22, 743–813.

COLLINS, F.S. (1896). Notes on New England marine algae-VII. Bull. Torrey Bot. Club 23, 458–462, Plate 278.

KUCKUCK, P. (1953). Herausgegeben von P. Kornmann. Ectocarpaceen-Studien I. Hecatonema, Chilionema, Compsonema. Helgol. wiss. Meeresunters. 4, 316–352.

SAUVAGEAU, C. (1897). Sur quelques Myrionemacees. Ann. Sci. nat.(Bot.), Ser. 8, 5, 161–288.

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

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
Part II
©Board of the Botanic Gardens and State Herbarium, Government of South Australia


Illustration in Womersley Part II, 1997: FIG. 115A,B.

Figure 115 image

Figure 115   enlarge

Fig. 115. A,B. Hecatonema maculans (ADU, A36893). A. Part of thallus with prostrate and erect filaments, longitudinal intercalary divisions, phaeophycean hairs, and plurilocular sporangia. B. Cells of an erect filament with phaeoplasts. C,D. Punctaria latifolia (ADU, A32867). C. Surface view of thallus with a hair tuft (lower right), and plurilocular and unilocular sporangia. D. Transverse section of thallus with phaeophycean hairs and plurilocular and (one) unilocular sporangia. E,F. Asperococcus compressus (ADU, A57205). E. Surface view of thallus and a sorus, with phaeophycean hairs, paraphyses and unilocular sporangia. F. Transverse section of thallus showing cavity crossed by filaments, and a sorus with phaeophycean hairs, paraphyses and unilocular sporangia.


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