Afrothismia winkleri develops fleshy rhizomes, densely covered with small root tubercles, narrowing to filiform
roots with age. The exclusively intracellular mycorrhizal fungus has distinct morphologies in different tissues of
the plant. In the filiform root the hyphae grow straight and vesicles are borne on short hyphal stalks. The straight
hyphae are present in the epidermis of the root tubercles, but change to loosely coiled and swollen hyphae in the
rhizome tissue. No penetration from epidermis to root cortex was found. From the rhizome, a separating cell layer
permits only one or rarely two hyphal penetrations into the cortex of each root tubercle. The hyphae proceed
apically within the root hypodermis in a spiral row of distinctively coiled hyphae, branches of which colonize the
inner root cortex. In the inner root cortex the hyphal coils degenerate to amorphous clumps. In older roots the
cortex itself also deteriorates, but epidermis, hypodermis, endodermis and central cylinder persist. The
mycorrhizal pattern in A. winkleri is interpreted as an elaborate exploitation system whereby the fungus provides
carbon and nutrients to the plant and, simultaneously but spatially distinct, its hyphae are used to translocate and
store the matter within the plant. Several features indicate that the endophyte is an arbuscular mycorrhizal fungus.