Electronic Flora of South Australia Species Fact Sheet
Phylum Chlorophyta – Order Derbesiales – Family Derbesiaceae
Selected citations: Boergesen 1925: 107, fig. 45. Feldmann 1937: 235, fig. 32A. Hamel 1930: 73, fig. 23, II, III. Kobara & Chihara 1980: 216, figs 14–23. MacRaild 1974: 99. Newton 1931: 100, fig. 66. Rietema 1975: 70, pls 17, 18. Sears & Wilce 1970: 383, figs 29, 30. Ziegler & Kingsbury 1964: 105, figs 1,2.
Sporophytic thallus (Fig. 99B) epiphytic or epilithic, 1–4 (–6) cm high, arising from a branched rhizoidal base, with a tuft of erect, often distantly branched, filaments (Fig. 100A). Filaments (45–) 50–80 (–90) µm in diameter, cylindrical and fairly straight, slightly contracted at the base of laterals but usually without a cross septum (Fig. 100B); wall 2–4 µm thick: chloroplasts numerous and usually densely aggregated, lenticular, mostly 6–10 µm long and each with a pyrenoid (Fig. 100B).
Gametophytic thallus (Halicystis parvula) dioecious, ovoid, 3–10 mm long (Fig. 100D), occurring on crustose coralline algae; chloroplasts ovate to lenticular, each with a pyrenoid (Fig. 100E,F).
Reproduction: Sporophytic thallus: Sporangia (Fig. 100B,C) usually pyriform, tapering to their base, (160–) 200–300 (–400) long and (100–) 140–200 (–220) µm broad, cut off by a double septum at maturity.
Gametophytic thallus reproduction by biflagellate anisogametes (Kobara & Chihara 1980).
Type from Caprara, Italy, in RO(?)
Distribution: Mediterranean and temperate eastern Atlantic.
In southern Australia, known from Scott Bay (6 km W. of Fowler Bay), S. Aust., in reef pools (Womersky, 27.i.1951; ADU, A14988) and Vivonne bay, Kangaroo I., S. Aust., in heavily shaded pool, S. side of Ellen Point (Womersley, 30.i.1956 and 29.i.1957; A20276 and A20787 resp.). Probably also from Port Adelaide, S. Aust., 10–20 cm deep on Commercial Fishing Marina (Womersley, 10.iii.1982; ADU, A52985, sterile).
Taxonomic notes: Halicystis stage. Nora Creina, S. Aust., on crustose coralline in heavily shaded pool (Womersky, 28.ii.1983; ADU, A54009). Ninepin Point, Tas., 5 m deep on crustose coralline (A. Brown, 1.xi.1982; ADU, A53825).
The above sporophytic specimens of I). tenuissima are often more robust in diameter than the Northern Hemisphere plant. However, the lack of vegetative cross septa, the size of the pyrenoid-bearing chloroplasts, and the site and form of the sporangia are features of D. tenuissima. The Vivonne Bay specimens, in particular, agree well with this species.
BOERGESEN, F. (1925). Marine algae from the Canary Islands, especially from Teneriffe and Gran Canaria. I. Chlorophyceae. Biol. Meddr 5 (3), 1–123.
FELDMANN, J. (1937). Les Algues marines de la Cote des Albères. I–III. Cyanophycées, Chlorophycées, Phaeophycees. Rev. Algol. 9, 141–335, Plates 8–17.
HAMEL, G. (1930). Chlorophycées des côtes francaises. (Paris.)
KOBARA, T. & CHIHARA, M. (1980). Laboratory culture and taxonomy of two species of Halicystis (Class Chlorophyceae) in Japan. Jap. J Phycol. 28, 211–217.
MacRAILD, G.N. (1974). The taxonomy, life history and cytology of Bryopsis and related genera from southern Australia. (Ph.D. thesis, Univ. Melbourne.)
NEWTON, L. (1931). A handbook of the British seaweeds. (British Museum: London.)
RIETEMA, H. (1975). Comparative investigations on the life-histories and reproduction of some species in the siphoneous green algal genera Bryopsis and Derbesia. (Univ. Groningen.)
SEARS, J.R. & WILCE, R.T. (1970). Reproduction and systematics of the marine alga Derbesia (Chlorophyceae) in New England. J. Phycol. 6, 381–392.
ZIEGLER, J.R. & KINGSBURY, J.M. (1964). Cultural studies on the marine green alga Halicystis parvula-Derbesia tenuissima. I. Normal and abnormal sexual and asexual reproduction. Phycologia 4, 105–116.
The Marine Benthic Flora of Southern Australia Part I complete list of references.
Womersley, H.B.S. (31 May, 1984)
The Marine Benthic Flora of Southern Australia
©Board of the Botanic Gardens and State Herbarium, Government of South Australia
Illustrations in Womersley Part I, 1984: FIGS 99B, 100 A–F.
Figure 99 enlarge
Fig. 99. A.Derbesia marina (ADU, A53085). B. Derbesia tenuisssima(AD U, A20276). C–F. Pedobesia clavaeformisC. Living thallus with sporangia (ADU, A37816 collection). D,E. Prostrate disc, showing concentric growth sectors, and meristematic periphery. E. Surface detail of prostrate disc (culture material, from MacRaild & Womersley 1954, Figs 7.9).
Figure 100 enlarge
Fig. 100. A–C. Derbesia tenuissima (ADU, A20276). A. Habit, with sporangia. B. Filament (with chloroplasts) with young lateral sporangium. C. Mature sporangium. D–F. Halicystis parvula stage. D. Two thalli on crustose coralline algae (ADU, A53825). E,F. Chloroplasts (ADU. A54009).
State Herbarium of South Australia