Many life-cycle patterns are found in algae. However, there is no regular and fixed alternation of generation, as found in higher plants. In blue-green algae and certain chlorophyceae which reproduced asexually, there is an alternation generation.
Most algae have two recognisable phases - the sporophyte and the gametophyte. The main types of algal life cycles are exhibited by green algae. (Red algae have even more complicated life cycles!)
Some Green algae are unicellular and demonstrate the
simplest possible life cycles. A good example of this is provided by the life
cycle of the unicellular fresh-water alga, Chlamydomonas:
Complex plants always have a multicellular haploid (gametophyte) stage in their life cycle!
