New data on the ecology of germination of Althenia filiformis Petit. – The author investigated the natural environment where this species, halophyte and hydrophyte, germinates. The relationships between temperature, salt concentration of pools in whichAlthenia filiformislives, and the dormancy of seeds were examined. In particular the author studied the behaviour of this species considering the natural conditions of pools of Orbetello (Tuscany) and Simbirizzi (Sardinia).