When the spores are mature, what happens?
The sporangia are then __. Each sporangium has a specialized layer of cells called the __. The annulus consists of __. The function of the annulus is to __.
the protective layer that covers the sporangia dries up and folds back or falls off of the leaf
fully exposed to the air
cells that have very thick cell walls and it occurs as a band of cells
throw the spores out of the sporangium and into the air