When recalcitrant propagules (seeds) of Avicennia marina were stored in a dry air stream there was no significant change in their moisture content for 10 days, after which it declined rapidly. Seed viability remained high during this 10-d period, only then declining. Ultrastructural changes in embryonic root primordium cells during the 10-d storage period were similar to those characterizing germination. It is suggested that the continuation of germination processes after shedding may be responsible for the deterioration in stored recalcitrant seeds.