Campbell Island: VOUCHER SPECIMEN: LE 221994. COLLECTION SITES: Streams 3, 4, 5, and 6.

DESCRIPTION: Thallus monocentric. Zoosporangia spherical, oval, ovoid, pyriform or oblong, 20- 250 µm in diam., with a smooth orange-brown wall and several exit papillae 2-12 µm high and 5-18 µm in diam., filled by a gelatinous plug of hyaline material and separated from the inner part of sporangium by a septum (endo-operculum). Rhizoid axes arising from the periphery or base of the sporangium and spreading and branching in the substrate and also extending extramatrically in the surrounding water for a distance of up to 600 µm. Resting spores spherical, oval, irregular with a smooth thick wall, containing several orange-brown globules.

COMMENTS: This species, which is considered to be a very common soil saprotroph, occurs mostly on cellulose substrates (i.e., plant debris). It is easily isolated, using pieces of onion epidermis, from samples of water and soil. Karlingia rosea has been recorded from Europe, the Americas, and Africa. Like C. variabilis, it is one of the first species to colonise cellulose substrates in water.