Electronic Flora of South Australia Species Fact Sheet
Phylum Phaeophyta – Order Dictyotales – Family Dictyotaceae – Tribe Dictyoteae
Selected citations: Womersley 1967: 211.
Thallus (Fig. 69B) light to medium brown, 3–6 cm long, becoming alternately branched at intervals of 0.5–1 cm, branches 2–4 mm broad with slightly irregular margins, usually basally constricted and broadening above points of branching, axils acute to rounded, apices truncate and bearing terete to slightly compressed fibrils (Figs 69B, 70A), 1–4 times branched, 2–6 mm long and 120–200 µm in diameter. Holdfast rhizoidal; probably epilithic. Cortical cells 10–20 µm across, L/B 1–2 (–3). Medulla one cell thick centrally throughout the thallus (as far as known), 2 (–3) cells thick near the margins (Fig. 70B,C); thickness centrally 80–120 (–180) µm, marginally 150–180 µm thick above and 300–350 µm thick below. Hair tufts scattered.
Type from Rottnest I., W. Aust. (Walcott); in Herb. Agardh, LD, 49509; with 5 specimens on the type sheet.
Distribution: Only known from the type collection.
Taxonomic notes: Dilophus crinitus may be based on specimens (possibly all from one clump) which are somewhat abnormal, since no similar specimens appear to have been collected since from Rottnest I., or nearby. The terminal fibrils to the branches in some cases appear to be natural, in other cases they may be proliferations following damage.
Although not known to occur in southern Australia, D. crinitus is included here to stimulate a search for further specimens in south-west Western Australia.
AGARDH, J.G. (1897). Analecta Algologica. Cont. IV. Ada Univ. lund. 33, 1–106, Plates 1, 2.
WOMERSLEY, H.B.S. (1967). A critical survey of the marine algae of southern Australia. II. Phaeophyta. Aust. J. Bot. 15, 189–270.
The Marine Benthic Flora of Southern Australia Part II complete list of references.
Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
©Board of the Botanic Gardens and State Herbarium, Government of South Australia
Illustrations in Womersley Part II, 1997: FIGS 69B, 70 A–C.
Figure 69 enlarge
Fig. 69. A. Dilophus tener (ADU, A38154). B. Dilophus crinitus (Herb. Agardh, LD, 49509, holotype). C. Dilophus fastigiatus (ADU, A56795).
Figure 70 enlarge
Fig. 70. A–C. Dilophus crinitus (ADU, A18579). A. End of a branch with fibrils. B. Transverse section of upper thallus. C. Transverse section of lower thallus. D–I. Dilophus fastigiatus (ADU, A30974). D. Surface view of thallus with tetrasporangia. E. Transverse section of thallus with undivided tetrasporangia. F. Surface view of thallus with oogonial sori. G. Transverse section of thallus with oogonial sori and a phaeophycean hair tuft. H. Surface view of thallus with antheridial sori. I. Transverse section of thallus with antheridial sori. J–M. Dilophus gunnianus (ADU, A56796). J. Surface view of thallus with tetrasporangia. K. Transverse section of upper thallus with undivided tetrasporangia. L. Transverse section of mid thallus with undivided tetrasporangia. M. Transverse section of lower thallus.
State Herbarium of South Australia