Some Observations on Plasmodia of the Trichiales

Abstract

Three distinct types of myxomycete plasmodia have been described. The microscopic "protoplasmodium" of certain minute species is a spherical mass with only irregular streaming and no formation of veins. The more complex "aphano-plasmodium" of some of the Stemonitales and the "phaneroplasmodium" of many of the Physarales grow to much larger size and are made up largely of a network of veins in which the protoplasm flows actively in streams rhythmically reversing their direction. Two members of the Trichiales, Hemitrichia vesparium and H. serpula, have plasmodia which are larger than the protoplasmodium but more delicate than the other 2 types. The main body of the plasmodium of the Hemitrichia spp. is a sheet-like mass in which the protoplasm flows rather irregularly, without delimitation into a network of individual veins. This, then, may be a valid 4th type of plasmodium, intermediate in position between the protoplasmodium and the more advanced aphanoplasmodium and phaneroplasmodium. The black granules of the plasmodium of H. vesparium act as pH indicators, so that the plasmodium is black at pH 5.0 through 8.0, brown at pH 3.0, orange at pH 2.0, and lemon-yellow at pH 1.0. At pH 9.0 through 11.0 it is red-brown, and at pH 13.0, brick-red. The stages of the fruiting process of H. vesparium are described.