In asexual reproduction , sporangiosphores are produced inside a spherical structure , the sporangium.

A single sporangium develops at the tip of long, erect sporangiosphore. 

A dome shaped columella is present in each sporangium. The protoplast of columella is in continuation with that of sporangiophores. 

The space between columella and wall of sporangia is known as spore sac. It remains filled wih sporangiospores.

Each sporangiospores is ovoid, non motile, unicellular and multinucleate structure. There is no flagella on the spores.