Gemmae can conveniently be split into two types.
Large fat gemmae. These cannot be stored and will start to grow even if
kept at temperatures close to freezing.
Thin fishscale-like gemmae. These can be stored in a fridge at around 5C
for at least several months, if wrapped in damp paper tissue and stored in
a plastic bag. Store as many as you can as casualty rates can be high
(higher the longer you keep them). I have kept gemmae of D.x Lake Badgerup
for 5 months this way with around 70% losses.
All gemmae will perish is kept at below freezing temperatures for even very
short periods of time.
-- Phil Wilson (cp@pwilson.demon.co.uk)