The authors supposed this fungus was mycorrhizal. After all, the role of symbionts for endophytes of P. polyphylla was suggested by several authors. Tan et al. (2006), for instance, analysed microstructure and distribution of endophytic fungi of the roots of this perennial herb and they found the hyphae were colonized in cortex of rhizomes and adventitious roots. They infected the cortex parenchyma through epidermis and exodermis, and then, formed pelotons and expanded their occupying area of cortex. The pelotons were digested and absorbed in some cells. As there is some evidence to suggest that the asymptomatic association between endophytes and several plant species may be mutualistic (Bacon & White 2000) we cannot exclude that endophytic fungi form orchid mycorrhizae.