Reticulomyxa filosa Nauss 1949

Diagnosis: Plasmodium aquatic and semi aquatic, white, rarely shell pink. In semi- aquatic cultures concentrated in small heaps, in aquatic often extended in a broad sheet, the central plasmodial area measuring to 4 mm in diameter (6 mm when fully extended), almost immobile, with many parallel channels in which the flows are alternately opposed; the pseudopodia attaining a length of ten times the central area, occasionally exhibiting fusiform thickenings and small alveolar areas; mature plasmodium homogeneously finely granular, periodically migrates to new site and divides longitudinally into daughter plasmodia (usually 3), disperses spore-like bodies when transferred to fresh dish of water.

Ecology: The plasmodium of R. filosa was originally seen in a culture of slime-mold plasmodia which was started from decaying leaves on moist blotting paper. The leaves were collected in the woods in a depressed, soggy area, about five feet in diameter, that lies close to the edge of a tidal swamp in the metropolitan area of New York City.

Remarks: Nauss (1949) notices about the culture of this organism: R. filosa thrives best on pulverized wheat germ, which is sifted lightly on the cultures every day or so except when it is maturing. When the species is grown with certain slime-mold plasmodia, the pulverized rolled oats fed to them seems sufficient to keep R. filosa flourishing for long periods of time. Cultures are grown at room temperature and transferred about once a week.

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