Capillitial formation in the Myxomycetes

Abstract

Scope and Method of Study: This report was undertaken as a survey of the information available to date concerning capillitial formation in the Myxomycetes. Some attention was given to the phylogenetic and taxonomic position and the morphology of the group. The major theories advanced in explanation of this formation were treated in a historical context. Capillitial formation of the Stemonitaceae, Physarales and Trichiales was given detailed treatment. A brief account was given concerning environmental effects on the total fruiting process.

Findings and Conclusions: In the immature Trichialess and Physarales, the protoplasm becomes highly vacuolated. These vacuoles are formed by the liberation of water in which various materials furnishing the substances for capillitium formation within the vacuoles are dissolved. This vacuolar system corresponds to the appearance of the capillitium in a mature sporangium. In the Physarales the capillitial material is deposited on the surface of the vacuoles. In the Stemonitales and Echinosteliales the capillitium either forms as an outgrowth of the columella or is deposited in the cytoplasm without previous formation of a vacuolar system. Environmental influences can only be inferred from data regarding environmental effects on the total fruiting process.