Electronic Flora of South Australia Species Fact Sheet

Dasya capillaris Hooker & Harvey in Harvey 1847: 60, pl. 19.

Phylum Rhodophyta – Order Ceramiales – Family Dasyaceae

Selected citations: J. Agardh 1863: 1212; 1890a: 102. De Toni 1903: 1200. Gepp & Gepp 1906: 258(?). Harvey 1859b: 302; 1863: synop.: xxii. Hooker & Harvey 1847: 400. Lucas 1912: 158; 1929a: 23; 1929b: 52. Lucas & Perrin 1947: 313. Sonder 1881: 36. Womersley 1950: 181.

Thallus (Fig. 217A) medium red, soft and lax, 7–25 cm high, with one to several slender axes, much branched laterally to subdichotomously, bearing above slender tufts of pseudolaterals, denuded below. Main axes terete, 200–800 (–1000) µm in diameter, corticated in their lower parts by rhizoids which develop 20–40 segments below the apices, lying at first between the pericentral cells and later covering the whole surface of the axis, with both large and small cortical cells in surface view; axes occasionally slightly spirally twisted. Lateral branches situated 2 or more segments apart, arising from the basal cell of the first branch of the pseudolateral, 1–4.5 cm long, lightly corticated only near their bases. Holdfast discoid, 1–5 mm across; on solid substrates. Structure. Pericentral cells 5, large and prominent, lightly corticated below with the segments visible through the cortex for most of the axes, remaining clear in section but with some corticating cells almost as large. Pseudolaterals (Fig. 217B) usually on every second segment, 1–4 mm long, subdichotomously branched below every 1–3 cells with ultimate simple branches 8–12 cells long; basal cells L/D 1–1.5, lower cells (15–) 25–35 (–40) µm in diameter and L/D (2–) 3–6 (–13), tapering to slender upper branches 6–12 µm in diameter and L/D 7–20. Lateral axes arising on the basal cell of the pseudolaterals.

Reproduction: Gametophytes dioecious. Procarps borne spirally on polysiphonous axes. Carposporophytes with a slight basal fusion cell, carposporangia in rows, slightly ovoid, 15–55 µm in diameter. Cystocarps sessile on lightly corticated polysiphonous axes, urceolate, 600–900 µm in diameter with a prominent neck about one quarter the cystocarp diameter in length. Spermatangial branches (Fig. 217D) replacing the ultimate branches of the pseudolaterals, sessile or on a 1 (–2)-celled monosiphonous stalk, cylindrical, 230–400 (–500) µm long and 25–40 µm in diameter, with 5–20 fertile segments and a sterile apical filament up to 6 cells long.

Stichidia (Fig. 217E) replacing the ultimate branches of pseudolaterals, on a 1 (–2)-celled monosiphonous stalk or occasionally sessile, cylindrical, 260–800 µm long and 70–110 µm in diameter with 5–20 fertile segments each with 4 pericentral cells and sporangia, terminated by 1–3 apical cells. Tetrasporangia 30–65 µm in diameter, each with 2 (–3) cover cells which are higher than broad and cover less than half of the tetrasporangium plus part of the sporangium of the segment below.

Type from Georgetown, Tas. (Gunn); lectotype (here selected) Gunn 1307; in Herb. Hooker, BM.

Selected specimens: Arno Bay, S. Aust., drift (Kraft 4211, 12.xi.1971; MELU and AD, A42248). N Spencer Gulf, S. Aust., 12 m deep (Shepherd, 6.ix.1973; AD, A44458) and 15 m deep (Shepherd, 5.ix.1973; AD, A44210). Kingscote, Kangaroo I., S. Aust., 6 m deep (Lavers, 7.vii.1997; AD, A67771).

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

Distribution: N Spencer Gulf and Kingscote, Kangaroo I., S. Aust., and N Tasmania. Probably more widespread but most records doubtful due to species confusion.

Taxonomic notes: Two descriptions of this species were published in 1847. Harvey's description in "Nereis Australis" is clearly the original, based on a specimen in TCD, and the Hooker & Harvey description in "Algae Tasmanicae" repeats the Nereis description (omitting two words) and refers to "Harv. Ner. Aust. p. 60, t.19". This original illustration of Harvey shows clearly the pseudolaterals 2 segments apart and their slender nature. Some specimens if not most of Harvey's Alg. Aust. Exsicc. 2061 (as D. capillaris), from Georgetown, Tasmania (illustrated by Kützing 1864, p. 26, pl. 73), have pseudolaterals from each segment and terminal clavate carposporangia. These are D. crescens; also some specimens of 2061 are D. hookeri.

Due to confusion with D. crescens and D. hookeri, and possibly other species, many records of D. capillaris must be considered doubtful. Well prepared slides of fertile material are necessary for sure determination of species.

References:

AGARDH, J.G. (1863). Species Genera et Ordines Algarum. Vol. 2, Part 3, pp. 787–1291. (Gleerup: Lund.)

AGARDH, J.G. (1890a). Till algernes systematik. Acta Univ. lund. 26(3), 1–125, Plates 1–3.

DE TONI, G.B. (1903). Sylloge Algarum omnium hucusque Cognitarum. Vol. 4. Florideae. Sect. 3, pp. 775–1521 + 1523–1525. (Padua.)

GEPP, A. & GEPP, E.S. (1906). Some marine algae from New South Wales. J. Bot., Lond. 1906, 249–261, Plate 481.

HARVEY, W.H. (1847). Nereis Australis, pp. 1–64, Plates 1–25. (Reeve: London.)

HARVEY, W.H. (1859b). Algae. In Hooker, J.D., The Botany of the Antarctic Voyage. III. Flora Tasmaniae. Vol. II, pp. 282–343, Plates 185–196. (Reeve: London.)

HARVEY, W.H. (1863). Phycologia Australica. Vol. 5, Plates 241–300, synop., pp. i-lxxiii. (Reeve: London.)

HOOKER, J.D. & HARVEY, W.H. (1847). Algae Tasmanicae. Lond. J. Bot. 6, 397–417.

KÜTZING, F.T. (1864). Tabulae Phycologicae. Vol. 14. (Nordhausen.)

LUCAS, A.H.S. & PERRIN, F. (1947). The Seaweeds of South Australia. Part 2. The Red Seaweeds. (Govt Printer: Adelaide.)

LUCAS, A.H.S. (1912). Supplementary list of the marine algae of Australia. Proc. Linn. Soc. N.S.W. 37, 157–171.

LUCAS, A.H.S. (1929a). The marine algae of Tasmania. Pap. Proc. R. Soc. Tasm. 1928, 6–27.

LUCAS, A.H.S. (1929b). A census of the marine algae of South Australia. Trans. R. Soc. S. Aust. 53, 45–53.

SONDER, O.W. (1881). In Mueller, F., Fragmenta Phytographiae Australiae. Supplementum ad volumen undecinum: Algae Australianae hactenus cognitae, pp. 1–42, 105–107. (Melbourne.)

WOMERSLEY, H.B.S. (1950). The marine algae of Kangaroo Island. III. List of Species 1. Trans. R. Soc. S. Aust. 73, 137–197.

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

Author: M.J. Parsons and 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. 217.

Figure 217   enlarge

Fig. 217. Dasya capillaris (AD, A44458). A. Habit. B. Axis with slight cortication and lateral with pseudolaterals 2 segments apart. C. Ruptured cystocarp with carposporophyte and ovoid carposporangia on right. D. Spermatangial branches. E. Stichidium with 4 tetrasporangia per segment.

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