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.
Key words: Afrothismia; Burmanniaceae; morphology; anatomy; myco-heterotrophy; arbuscular mycorrhiza..
