A Field Survey of Mycorrhizal Associations in Ferns of Pakistan

SUMMARY Roots of the ferns examined in this investigation were constantly mycorrhizal. A mixture of several endophytes infecting a root system was a usual feature of them. Vesicular‐arbuscular endophytes predominated over endophytes with a septate mycelium. Ectomycorrhizal fungi with a septate mycelium bearing clamp‐connections ran longitudinally inside the cortex and occasionally these hyphae formed a mantle on the outside of the roots. A displacement of endotrophic mycorrhizas by ectomycorrhizal fungi occurred in Adiantum vemistum D. Don when growing under pine forest. Heavy arbuscular and vesicular infections occurred throughout the period of investigation. Several spore types were present in each rhizosphere.