Noun
A spore case in the cryptogamous plants, as in ferns, etc.
Source: Webster's dictionaryThat is, some plants have distinct egg-producing and sperm-producing gametophytes, but these gametophytes develop from the same kind of spore inside the same sporangium; Sphaerocarpos is an example of such a plant. Source: Internet
Seed plant microgametophytes consists of two or three cells when the pollen grains exit the sporangium. Source: Internet