Bryophytes are homosporous and monoecious but why few are dioecious?
To get this answer first we need to know what is the homosporous condition?
The spores of bryophytes are highly specialised cells produced in the capsule of the sporophyte. These spores are morphologically alike in size and thus are homosporous. Each of the spores then germinates under suitable condition to give rise to the main gametophyte.
Monoecious and dioecious conditions refer to the gametophytic phase. With the initiation of this phase two kinds of sex organs appears ie., antherdia and archegonia. If these sex organs are developed on the same thallus, such species are monoecious (Riccia sp). On the contrary if antherdia and archegonia are borne on different thalli then they are dioecious eg., Marchantia sp.