- Reference
- Mar.Benth.Fl.S.Australia 265 (1996)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus encrusting or warty, 0.15–4 mm thick, epilithic or epizoic and affixed by cell adhesion. Structure pseudoparenchymatous; organization dorsiventral; construction monomerous, consisting of a single system of branched filaments that collectively contribute to a ventrally situated core, and a peripheral region where portions of core filaments or their derivatives curve outwards towards the thallus surface, each filament composed of cells 2–6 µm in diameter and 2–17 µm long; a single epithallial cell terminating most filaments at the thallus surface, distal walls rounded or flattened but not flared; cells of adjacent filaments joined by cell-fusions, secondary pit-connections absent; trichocytes occurring commonly at thallus surface, arranged in horizontal fields or singly, not becoming buried within the thallus.
Reproduction.Vegetative reproduction unknown. Gametangia, carposporangia and tetrasporangia produced in uniporate conceptacles; bisporangia unknown. Gametangial plants monoecious; carpogonia and spermatangia produced in separate conceptacles. Carpogonia terminating 3-celled filaments arising from the female conceptacle chamber floor. Mature female-carposporangial conceptacle roofs flush with surrounding thallus surface, usually composed of 3 cells above the chamber, conceptacle chambers 77–104 µm in diameter and 63–90 µm high. Carposporophytes developing within older female conceptacles after karyogamy, when mature composed of a large central fusion cell and gonimoblast filaments bearing terminal carposporangia, pore canals formed perpendicularly to thallus surface. Spermatangial filaments unbranched, arising from the floor of male conceptacle chambers, mature male conceptacle roofs flush with surrounding thallus surface, composed of 3 or 4 cells, conceptacle chambers 49–55 µm in diameter and 41–49 µm high. Tetrasporangial conceptacle roofs flush with surrounding thallus surface, 3 or 4 cells thick above the chamber, pore canals lined with non-protruding cells, conceptacle chambers 82–96 µm in diameter and 82–77 µm high; tetrasporangia scattered across chamber floor, each mature sporangium 15–35 µm in diameter and 40–55 µm long, zonately divided.
Distribution.Lucky Bay, W. Aust., eastwards to Phillip I., Vic., and from Cape Green, southern N.S.W.
Habitat. H. rupestris occurs commonly on intertidal rock platforms in southern Australia.
[After Womersley, Mar. Benthic Fl. Southern Australia IIIB: 265–266 (1996)]