A New Gonimochaete with an Oospore State

Gonimochaete lignicola is described as a new species of nematode-destroying endoparasite recovered from rotting wood. Segments of the infection thallus function as sporangia and produce solitary aerial evacuation tubes. The protoplasm in the sporangium migrates to the swollen tip of the evacuation tube where it differentiates into spores. The tip of the evacuation tube is cut off by a septum from the vacuolated remainder either before or after spore formation. Some thalloid segments function as antheridia or oogonia. The protoplasm migrates from the antheridium into the oogonium and a solitary, thick-walled, pitted oospore is produced. This is the first time the sexual state has been described for a species of Gonimochaete and supports placement of this genus in the Lagenidiales.