Medium- and long-term storage of the Pycnanthemum (mountain mint) germplasm collection.

The United States of America collection of mountain mint (Pycnanthemum Michx.) is held at the USDA-ARS National Clonal Germplasm Repository (NCGR) in Corvallis, Oregon as seed, potted plants and tissue cultures and a long-term storage collection is preserved at the USDA-ARS National Center for Genetic Resources Preservation (NCGRP) in Fort Collins, Colorado. The clonal collection is comprised of 34 accessions as potted plants that are duplicated with 31 accessions stored as in vitro cultures at 4 degrees C in tissue culture bags for medium-term storage at NCGR and as cryopreserved shoot tips in liquid nitrogen at NCGRP for long-term storage.