Foraging patterns of Phallus impudicus, Phanerochaete laevis and Steccherinum fimbriatum between discontinuous resource units in soil

Wood blocks colonised by the basidiomycetes Phallus impudicus, Phanerochaete laevis and Steccherinum fimbriatum were placed individually in plastic trays containing moist, unsterilised soil. All three fungi grew out radially from the inoculum blocks, forming networks of mycelial cords. Outgrowth patterns of P. impudicus and P. laevis were similar in controls to those in experiments where a second uncolonised wood block was placed as a ‘bait’ several centimetres away from the inoculum block. However, contact with the bait by S. fimbriatum resulted in marked changes in growth pattern. These changes included cessation of radial extension from the inoculum, thickening of connective mycelium between inoculum and bait, outgrowth from the bait in the original direction of travel and regression of non-connective mycelium. These observations emphasize the collective organisation of mycelial systems and the differences in their growth pattern which can arise from varying foraging strategies.