This is a cartoon (click for a larger version) of the heteromorphic alteration of generations life history of Desmarestia ligulata from Carmel Bay California as explained by Matthew S. Edwards. During the summer months thalli of this alga are abundant and can grow up to two meters high. During the winter months, the sporophytes die off and the microscopic gametophytes survive.
This is a drawing of the structure, called unilocular
sporangia, where meiosis occurs to produce haploid spores, found in
mature, fertile sporophytes - the diplontic stage of the life cycle.
Unilocular means that there is a single compartment in which several
spores are produced.
© 2005 Ashley Maloney