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The subterranean organs of Afrothismia gesnerioides H. Maas consist of short rhizomes densely covered with ovoid root tubercles, each of which may extend into a short filiform root extension. Serial sections revealed the presence of two distinct fungi occupying different niches within the plant tissues. Rhizomes and roots are divided into separate compartments hosting different morphotypes of the aseptate, exclusively intracellular hyphae of fungus A: (i) straight and persistent hyphae in the root epidermis, root extension, and outer rhizome cortex, (ii) coiled but still persistent hyphae in the third root layer, (iii) coiled hyphae undergoing degeneration in the root cortical parenchyma, (iv) starch depositions in the inner rhizome cortex and no colonization by fungus A, and (v) a partly collapsed root hypodermis serving as compartment barrier. The colonization by fungus A is interpreted as an aberrant arbuscular …