Electronic Flora of South Australia Species Fact Sheet

Jania parva Johansen & Womersley 1994: 609, figs 1–5,21–26.

Phylum Rhodophyta – Class Florideophyceae – Order Corallinales – Family Corallinaceae – Subfamily Corallinoideae – Tribe Janieae

Thallus (Fig. 135A) light grey-red, 2–5 mm high, slender, branching divaricate, with 1–7 erect fronds from each holdfast, stolons lacking; fronds usually 10–30 intergenicula long, branching in varying planes every 2–10 (–15) intergenicula; intergenicula terete, 55–80 µm in diameter below, 30–50 µm in diameter above, 165–275 (–300) µm long and L/D 3–5 (–7). Holdfasts thin crusts, (200–) 300–500 µm across; epiphytic on Posidonia and Halophila. Structure of intergenicula with (1–) 2–3 tiers of medullary cells each 60–90 µm long, and a cortex one cell thick; genicula 60–90 µm long.

Reproduction: Gametangial thalli monoecious, with distinct female and male branches from one holdfast. Female conceptacles (Fig. 135A, B) in branched fronds; conceptacles amphoroid, externally 240–330 µm long and 160–240 µm in diameter, internally 100–160 µm in diameter, with 2–5 mature ovoid-angular carposporangia per conceptacle, each 40–65 µm in diameter. Male conceptacles (Fig. 135C, D) terminal in simple or 1–2 branched fronds, externally 200–280 µm long and 100–160 µm in diameter, internal diameter 70–90 µm.

Bisporangial conceptacles (Fig. 135E) amphoroid, externally 250–350 µm long and 200–250 µm in diameter, internal diameter 140–190 µm; tetranucleate (two nuclei in each spore) bisporangia 2–5 per conceptacle, 120–180 µm long and (40–) 60–90 µm in diameter; tetras porangi a unknown.

Holotype from Stansbury, S. Aust., 2–3 m deep on Posidonia australis (Womersley, 14.x.1989); in AD, A59922.

Selected specimens: Point Turton, S. Aust., on Posidonia sinuosa, drift (Warnersley, 15.x.1989; AD, A59928). Stansbury, S. Aust., on P. australis drift (Womersley, 14.x.1989; AD, A59919). Pelican Lagoon, American R. inlet, Kangaroo I., S. Aust., 1–2 m deep on P. australis (Warnersley, 7.i.1990; AD, A60105 -"Marine Algae of southern Australia" No. 342). Bay of Shoals, Kangaroo I., S. Aust., on P. australis, 0–3 m deep (Womersley, 5.i.1990; AD, A60107, A60099 and A60118), and on Halophila australis, 3 m deep (Womersley, 5.i.1990; AD, A60117).

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

Distribution: Point Turton, S. Aust., to American R. inlet, Kangaroo I., S. Aust. (probably more widely distributed in calm water localities).

Taxonomic notes: Jania parva is similar in frond size to J. minuta, but branching tends to be divaricate rather than fastigiate, intergenicula are longer, intergenicular length to diameter ratios are greater (3–5 vs. 1–2), and sporangial conceptacles are amphoroid. Based on divaricate branching and intergenicular length to diameter ratios, J. parva is more closely related to the common tropical J. adhaerens Lamouroux than to J. minuta.

References:

JOHANSEN, H.W. & WOMERSLEY, H.B.S. (1994). Jania (Corallinales, Rhodophyta) in southern Australia. Aust. Syst. Bot. 7, 605–625.

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

Author: H.B.S. Womersley & H.W. Johansen

Publication: Womersley, H.B.S. (28 June, 1996)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIB. Gracilarialse, Rhodymeniales, Corallinales and Bonnemaisoniales
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIB 1996, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

Illustration in Womersley Part IIIA, 1996: FIG. 135.

Figure 135   enlarge

Fig. 135. Jania parva (AD, A59922). A. Habit. B. Carposporangial conceptacles. C. Two male conceptacles. D. A male conceptacle. E. Two bisporangial conceptacles.

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