Andreaea nivalis

The sporangium of the lantern moss is open here, to disperse spores. A few spores can be seen inside. When the sporangium is dry, it opens along 4 or 5 longitudinal slits, and the columella (like a post in the middle) compresses. If it is rewetted, it can close again. The sporangium may open and close many times, dispersing the spores over a long period of time.