These can be observed in situ or by washing soil from roots very gently. Observations of fresh roots with a dissecting microscope normally allow ECM roots to be identified and quantified. The higher level of magnification provided by a compound microscope allows mycorrhizal structures within roots to be seen. Thin sections of roots reveal structural details of mycorrhizas. Whole roots or root sections can be cleared and stained to remove root pigments and show fungus hyphae.
Microscopic observations can confirm the identity of fungi and reveal their spores.
C. Structures and Developmental Stages Ectomycorrhizas form by synchronised growth by host roots and compatible fungi when environmental conditions are favourable. These events are summarised below. Most plants with ECM have roots with a modified lateral root branching pattern. Thus, trees with ECM would require slow growth of some of their lateral roots, and in time, this process would result in the evolution of separate, genetically distinct long and short roots. The long roots of many species rapidly develop a periderm , which would prevent them from forming mycorrhizas.