How do fern sporangia release their spores?

In most ferns, the mechanism for spore release depends on the type of sporangium:

• Leptosporangia: These structures, found in the majority of fern species, utilize a specialized row of cells called an annulus to release spores explosively. As the annulus dries, the cohesive forces of water molecules cause the cells to deform, straightening the annulus and tearing the capsule open. When the tension of the water film is finally exceeded, the annulus snaps back to its original position, effectively tossing the spores into the air.12
• Eusporangia: Found in more primitive ferns, these sporangia have thicker, multi-layered walls and lack a specialized mechanism for throwing spores. Instead, the capsule opens along a line of dehiscence due to stress from drying walls, and the spores are simply dispersed by the wind.12