- Reference
- Phycologia 141 (1994)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus encrusting, epiphytic and affixed by cell adhesion. Structure pseudoparenchymatous; organization dorsiventral; construction dimerous, consisting of a single ventral layer of branched filaments composed on non-palisade cells, and unicellular or multicellular simple or branched filaments that arise more or less perpendicularly from cells of ventral layer filaments, each filament composed of cells 2–15 µm in diameter and 2–20 µm long; epithallial cells 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 present or absent, if present, usually occurring singly or in pairs at the thallus surface, not becoming buried within the thallus.
Reproduction. Vegetative reproduction unknown. Gametangia, carposporangia, tetrasporangia and bisporangia produced in uniporate conceptacles. 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 protruding above or flush with surrounding thallus surface composed of 4–6 cells above the chamber, pores surrounded by coronas of filaments, conceptacle chambers 135–250 µm in diameter and 135–180 µm high. Carposporophytes developing within older female conceptacles after karyogamy, when mature composed of a large central fusion cell and with gonimoblast filaments bearing terminal carposporangia. Spermatangial filaments unbranched, arising from the floor of male conceptacle chambers, mature male conceptacle roofs protruding above or flush with surrounding thallus surface, conceptacle chambers 50–70 µm in diameter and 30–55 µm high. Tetrasporangial and bisporangial conceptacle roofs protruding above or flush with surrounding thallus surface, 3–6 cells thick above the chamber, pore canals lined with protruding cells, pores surrounded by coronas of filaments, conceptacle chambers 135–235 µm in diameter and 85–185 µm high; tetrasporangia and bisporangia scattered across the conceptacle chamber floor or peripheral to a central columella, each mature sporangium 15–45 µm in diameter and 40–80 µm long, zonately divided.
Distribution.The Malay Archipelago; New Zealand; tropical W. Aust. In southern Australia, Point Sinclair, S. Aust., eastwards to Sorrento, Vic., and around Tas.
Habitat. P. coronatum commonly grows intermixed with P. fragile on various algae and on the seagrass Amphibolis antarctica.
[After Womersley, Mar. Benthic Fl. Southern Australia IIIB: 267–269 (1996)]