There was large inter- and intraspecific variation in the development of external hyphae by the ecto- mycorrhizal fungi (Fig. 4). The L. laccata isolates generally formed a greater length of hyphae in soil than the other fungal isolates at 63 and 87 d, which corresponds with a greater length of external hyphae per m of fine root and per m of colonized fine root for these fungi (Fig. 4). D. maculata formed the least amount of external hyphae per m of colonized fine root at 87 d.