Thus in the Rhizocarpæ there are two kinds of spores, microspores and macrospores, producing prothallia which bear respectively antheridia and archegonia; in the Lycopodiaceæ, the two kinds of spores produce very rudimentary prothallia; in the cycads and conifers, the microspore or pollen grain only divides once or twice, just indicating a prothallium, and no antheridia or antherozoids are formed.