The life-history of Cystochytrium radicale occurring in the roots of Veronica beccabunga

Abstract

1. A new species of fungus belonging to the Chytridiales is described under the name Cystochytrium radicale , which attacks the roots of Veronica Beccabunga . 2. A uninucleated zoospore enters and grows within the cells of the host, later becoming multinucleate and enclosed in a chitinous sheath. When mature the soma functions as a zoosporangium and produces about eight zoospores which escape through a pore in the thickened wall of the zoosporangium. 3. The zoospores are spherical, 12–15 μ in diameter, and possess one flagellum. They make their way out of the root and swim in the water around them and infect fresh roots. 4. The host plant is not visibly affected by the presence of the fungus which sometimes occurs in a particular root in large numbers. 5. The relationships of the fungus are discussed, and it is suggested that it should be placed in the Hyphochytridiaceae, in a new genus somewhat closely allied to Hyphochytrium .