EPULORHIZA INQUILINA SP NOV. FROM PLATANTHERA (ORCHIDACEAE) AND A KEYTO EPULORHIZA SPECIES

Epulorhiza inquilina sp. nov. is described from the mycorrhizas of mat ure plants of Platanthera clavellata, P. cristata and P. integrilabia, coexisting terrestrial orchids native to bogs in the southern Appalac hians. The new taxon was isolated consistently and exclusively from th ese orchid taxa over a seven-year period. Protocorms from seeds of P. integrilabia planted in their native habitat were also colonized by E. inquilina and consequently some specificity in the symbiosis is suspe cted. E. inquilina is binucleate and has imperforate parenthesomes but differs from other species in the genus because of its woolly colonia l morphology, tan colour on artificial media, and its elongate monilio id cells that develop in relatively short chains. The five species of Epulorhiza are distinguished in a key.