Spore (n) is the first cell of the gametophyte. Spores are small, more or less round with a smooth exine and inner hyaline intine.
Each spore germinates within a few days of fall on suitable substratum. It develops into filamentous, branched multi cellular peritonea composed of two distinct parts, (i) sparsely and irregularly branched chloronema which grow above the soil and are green in color.
They develop into leafy gametophores, (ii) profusely and regularly branched caulonema which grow downwards in the soil. They are also called as rhizoidal branches. They absorb water and nutrients and anchor the protonema to the soil.