Electronic Flora of South Australia Species Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Phyllophoraceae
Gymnogongrus humilis Lindauer 1947 (Alg. Nova-Zel. Exsicc. 145). Chapman 1979: 362, fig. 98B, pl. 147.
Thallus (Fig. 84C, D) dark red-brown, 1–2 (–4) cm high, drying cartilaginous, more or less complanately branched and subdichotomous at intervals of 5–15 mm, margins smooth or with small proliferations, sometimes proliferous above (following damage?), branches flat, (0.5–) 1–1.5 mm broad (narrower near their bases), with rounded to somewhat truncate apices. Holdfast thin, crustose, 1–4 mm across, with one to numerous erect fronds; epilithic. Structure multiaxial with ovoid cells throughout, cortical cells in short anticlinal rows of 2–3 cells, outer cells 2–4 µm in diameter and L/D 1.5–2, medullary cells 20–60 (–80) µm in diameter and L/D 1.5–3 (–6), often tiered in longitudinal section and with numerous secondary pit-connections. Rhodoplasts discoid, becoming elongate in inner cells, few to several per cell.
Reproduction: Carpogonial branches unknown. Cystocarps (Fig. 84E) in the upper branches, slightly to moderately swollen, 300–800 µm across, the carposporophyte lying in the medulla and consisting of numerous separated gonimoblast cells producing clusters of ovoid carposporangia 6–10 µm in diameter; pericarp and ostiole absent. Spermatangia unknown.
Type from Ngaere Bay, Northland, New Zealand, at low water (Lindauer 145, 25.ii.1940); lectotype in Herb. Lindauer, CHR; isolectotypes distributed in Alg. Nova-Zel. Exsicc. 145.
Distribution: New Zealand.
In southern Australia, from Robe, S. Aust., to Aireys Inlet, Vic.
Taxonomic notes: G. humilis becomes fertile when only 1–2 cm tall and with only a few branches, and under better conditions reaches 3 cm high with proliferous branching above, possibly following damage. Plants in the MELU, A39450 collection from Robe match the type well and other collections of A. humilis from New Zealand [e.g. Ahipara, New Zealand, low intertidal (Kraft, 14.x.1972; MELU, A40409)] but other collections are slenderer and have more rounded apices than the New Zealand plants. The vegetative and carposporophyte structure observed in both the type and Australian specimens is consistent with Ahnfeltiopsis, but further studies on its reproduction and life history are needed. Some plants have ovate, raised pustules (Fig. 84F) of erect filaments, each arising from an outer cortical cell, filaments 5–8 µm in diameter, cells L/D 1–2, simple or occasionally branched and with numerous lateral secondary pit-connections; the function of these pustules is unknown.
CHAPMAN, V.J. (1979). The marine algae of New Zealand. Part DI Rhodophyceae. Issue 4: Gigartinales. (Cramer: Germany.)
LINDAUER, V.W. (1947). Algae Nova-Zelandicae Exsiccatae. Fasc. 6, numbers 126–150. (Issued Dec. 1942, description May 1947.)
The Marine Benthic Flora of Southern Australia Part IIIA complete list of references.
Womersley, H.B.S. (14 January, 1994)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIA, Bangiophyceae and Florideophyceae (to Gigartinales)
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIA 1994, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.
Illustration in Womersley Part IIIA, 1994: FIG. 84 C–F.
Figure 84 enlarge
Fig. 84. A, B. Ahnfeltiopsis fastigiate (A, MELU, A39459; B, AD, A27731). A. Habit. B. Transverse section of cystocarp. C–F. Ahnfeltiopsis humilis (C, E, F, AD, A61516; D, AD, A21294). C. Habit, mature plants. D. Habit of larger, much branched, plant. E. Transverse section of cystocarp. F. Transverse section of thallus with surface pustule. G, H. Gymnogongrus griffithsiae (AD, A20336). G. Habit. H. Longitudinal section of thallus with tetrasporoblast pustules.
State Herbarium of South Australia