Electronic Flora of South Australia Species Fact Sheet

Hildenbrandia crouanii J.Agardh 1852: 495; 1876: 379.

Phylum Rhodophyta – Class Florideophyceae – Order Hildenbrandiales – Family Hildenbrandiaceae

Selected citations: Denizot 1968: 199, fig. p. 196. Rosenvinge 1917: 207, fig. 126.

Thallus medium to dark red, (1–) 3–12 mm across, very thin (80–240 µm thick) and tightly adherent to rock, usually intertidal. Structure (Fig. 42B). Basal layer of irregularly radiating, branched, filaments 3–5 µm in diameter, cells (within margin) L/D 1–2, becoming several cells thick with rounded cells 5–7 µm in diameter. Erect filaments 40–200 µm and 15–40 cells long, 3–6 [tin in diameter with cuboidal cells, L/D 0.6–1.5; rhodoplasts single per cell.

Reproduction: Conceptacles (Fig. 42B) subspherical to ovoid, 50–80 µm in diameter with an ostiole 20–45 µm across; tetrasporangia 6–10 µm in diameter and 15–20 µm long, zonately divided with oblique cross walls; paraphyses absent but old sporangial walls remaining.

Type from Brest, France (Crouan); in Herb. Agardh, LD.

Selected specimens: Point Drummond, S. Aust., mid eulittoral in shade (Womersley, 11.i.1951; AD, A15068). Middle R., Kangaroo I., S. Aust., lower eulittoral (Womersley, 21.i.1948; AD, Al2973). Ballast Head, Kangaroo I., S. Aust., low eulittoral (Womersley, 3.i.1948; AD, Al2965). Cape Willoughby, Kangaroo I., S. Aust., mid eulittoral (Womersley, 8.i.1950; AD, Al2966).


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

Distribution: Widespread on temperate coasts.

In southern Australia, from Point Drummond to Cape Willoughby, Kangaroo I., S. Aust., but probably more widespread.

Taxonomic notes: H. crouanii differs from H. prototypus essentially in having obliquely zonate division of the tetrasporangia, but these are somewhat variable and further study is needed of such differences.

References:

AGARDH, J.G. (1852). Species Genera et Ordines Algarum. Vol. 2, Part 2, pp. 337–720. (Gleerup: Lund.)

AGARDH, J.G. (1876). Species Genera et Ordines Algarum. Vol. 3, Part 1 - Epicrisis systematis Floridearum, pp. i-vii, 1–724. (Weigel: Leipzig.)

DENIZOT, M. (1968). Les Algues Floridées encroûtantes (a l'exclusion des Corallinacées). (Paris.)

ROSENVINGE, L.K. (1917). The marine algae of Denmark. Part II. Rhodophyceae (Cryptonemiales). K. danske Vidensk. Selsk. Biol. Skr., 7 Raekke, Afd. 7, 153–283, Plates 3, 4.

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

Author: H.B.S. Womersley

Publication: 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. 42B.

Figure 42 image

Figure 42   enlarge

Fig. 42. A. Hildenbrandia rubra (AD, A60783). Cross section of thallus with a conceptacle and irregularly divided tetrasporangia. B. Hildenbrandia crouanii (AD, Al2966). Cross section of thallus with a conceptacle with tetrasporangia divided by obliquely zonate walls. C. Hildenbrandia lecannellieri (AD, Al2986). Cross section of thallus and conceptacle (in part) with zonately and irregularly divided tetrasporangia. D. Hildenbrandia expansa (AD, A60088). Cross section of thallus and conceptacle (in part) showing regular horizontal and vertical rows of cells, with horizontal layers of larger cells (arrows), and zonately divided tetrasporangia with paraphyses. E–H. Rhodopeltis australis (E, AD, A15518; F, AD, A8320; G, AD, A34997; H, AD, A38735). E. Section of female nemathecium with a carpogonial branch and an auxiliary cell branch among paraphyses. F. Section of a female nemathecium with a carposporophyte borne on an auxiliary cell. G. Section of a male nemathecium with spermatangial branches. H. Section of outer cortex (with inner stellate cells) with tetrasporangia among short paraphyses.


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