Glomus multiforum and G. verruculosum, two new species from Poland

Two new vesicular-arbuscular mycorrhizal fungal species, Glomus multiforum and G. verruculosum (Glomales, Zygomycetes) coming from northwestern Poland are described and illustrated. Glomus multiforum produces spores singly in the soil. The deep yellow to brown spores are globose to subglobose, (170-)215(-230) μm diam or ovoid, 150-220 × 180-310 μm and have a single wall consisting of three layers. Outermost layer 1 is mucilaginous, hyaline, and stains reddish in Melzer's reagent. Layer 2 of young spores is hyaline and ornamented with ingrowths filling the pits of layer 3; it sloughs with spore age. Layer 3 is laminated, colored and ornamented with evenly distributed pits. Glomus verruculosum forms spores singly in the soil. Spores are yellow to orange, (150-)189(-265) μm diam. Their single wall consists of two layers: a hyaline, semiflexible outer layer and a yellow to orange, laminated inner layer ornamented with warts projecting inward from the innermost lamina. None of these layers stain in Melzer's reagent. Both G. multiforum and G. verruculosum formed spores and vesicular-arbuscular mycorrhizae in single-species pot cultures with Plantago lanceolata and Sorghum sudanense.