very of mycelial mass, from two microscopic spores into tons of mycelium in a matter of weeks, mushroom mycelium cell division potential far exceeds that of most organisms. Nevertheless, strains die and, unless precautions have been taken, the culture may never be retrieved.
Once a mushroom strain is taken into culture, whether from spores or tissue, the resultant strains can be preserved for decades under normal refrigeration, perhaps centuries under liquid nitrogen. In the field of mycology, cultures are typically stored in test tubes. Test tubes are filled with media, sterilized and laid at a 15-20 degree angle on a table to cool. (Refer to Chapter 12 for making sterilized medie.) These are called test tube starts. Once inoculated, these are known as culture slant.