Spores of VAM Fungi Inside Spores of VAM Fungi

Dead spores of at least 10 species of vesicular-arbuscular mycorrhizal (VAM) fungi, mostly members of the genus Gigaspora, were occupied by spores of other species of VAM fungi in sand dunes of the Atlantic Coast of the U.S. and of the Great Lakes. Species of Gigaspora, Acaulospora, and Glomus were involved in such associations. Spores of 1–5 different species occurred within single dead spores and individual spores contained 1–100 spores. Samples from sand dunes at Virginia Beach contained the greatest percentage of occupied spores. In some root-zone samples, the ratio of occupied Gigaspora spores to intact spores was as high as 5:1. The VAM species most frequently sporulating within other VAM spores was a Glomus sp. resembling a fossil species described by Butler in 1939.