Propagation of the little club-spur orchid (Platanthera clavellata) by symbiotic seed germination and its ecological implications

Abstract Propagation of the auto-pollinated terrestrial orchid, Platanthera clavellata , using symbiotic seed germination is described. Seed from three populations in the southern Appalachians (Tennessee, South Carolina, GA) were inoculated with mycorrhizal fungi ( Epulorhiza spp.) in vitro; seed germination and protocorm (seedling) developmental stages were evaluated up to 1 year after sowing. Seed obtained from Tennessee and South Carolina populations had a significantly higher percent germination (76.4 and 81.5%, respectively) than those collected from Georgia (16.2%); however, the Georgia population yielded more advanced seedlings suitable for soil transfer. A single fungal isolate ( E. inquilina ) originally obtained from the roots of P. clavellata , promoted advanced seedling development; three other isolates from additional Platanthera taxa ( P. ciliaris , P. cristata , P. integrilabia ), were ineffective. The ecological role of this orchid with its associated fungi is discussed with respect to the other co-habiting Platanthera species.