Nature of the "black line" produced between different biological species of the Armillaria mellea complex

Abstract

The zone of antagonism or black line, formed between the confronting margins of different biological species of the Armillaria mellea complex when paired on malt agar medium, was investigated. Light microscopy showed that the black line was composed of melanized hyphal cells from both species and was bordered on either side by the bladderlike cells of the pseudosclerotial plate of each species.