The spores are high in an oil that is flammable and explosive, used in fireworks and gunpowder. More advanced plants are less dependent on water to transport reproductive cells. Homosporous plants have one type of spore. Bryophytes, whisk ferns, horsetails, most ferns, club mosses. Microspores develop into male gametophyte that produces sperm in atheridia.
Microspores develop into female gametophyte that produces egg in archegonium.