Red algae
Life cycle

They display alternation of generations. In addition to a gametophyte generation, many have two sporophyte generations, the carposporophyte -producing carpospores, which germinate into a tetrasporophyte – this produces spore tetrads, which dissociate and germinate into gametophytes. The gametophyte is typically (but not always) identical to the tetrasporophyte.

Carpospores may also germinate directly into thalloid gametophytes, or the carposporophytes may produce a tetraspore without going through a (free-living) tetrasporophyte phase. Tetrasporangia may be arranged in a row (zonate), in a cross (cruciate), or in a tetrad.

The carposporophyte may be enclosed within the gametophyte, which may cover it with branches to form a cystocarp.

The two following case studies may be helpful to understand some of the life histories algae may display:

In a simple case, such as Rhodochorton investiens:

A rather different example is Porphyra gardneri:
startend:end_checker