Ectomycorrhiza formation in Eucalyptus. III. Superificial ectomycorrhizas initiated by Hysterangium and Cortinarius species

Cortinarius and Hysterangium species are a dominant component of the macrofungi in eucalypt forests of Western Australia, and their hyphae occupy 10 % of the soil surface area. Anatomical studies of jarrah (Eucalyptus marginata Donn ex Sm.) and karri (E. diversicolor F. Muell) roots collected in association with hyphae of Cortinarius globuliformis Boug., C. ochraceus Clel. and Hysterangium inflatum Rodway showed mycorrhizal structures with mantles one to five cells thick and Hartig nets penetrating to the hypodermis. These superficial ectomycorrhizas were similar in size to those of non‐colonized feeder roots and lacked the expanded cortex and broad mantle of pyramidal ectomycorrhizas formed by Laccaria laccata (Scop, ex Fr.) Berk. & Br. Colonized host roots responded with polyphenol accumulation in the epidermis/hypodermis and lignification of the outer cortex for both the superficial and pyramidal types