Asexual reproduction uses the technique of spore formation. In sacs referred known as Sporangia, many spores are kept. 

Sporangia burst, releasing tiny single-celled, thin or thick-walled objects known as spores. 

They grow into a new Plant when the right circumstances are present.

Spores are an asexual means of reproduction. 

The knob-like sporangia are structures. They are located at the very top of the hyphal structures, which are thread-like. They are dispersive, which means that rain, wind, or insects can disperse them.