Swimming sperm are seen shortly after adding water to cultures but seem to disappear quickly.

If water is added to a C-Fern culture, sperm are typically released quickly – within a few minutes. Because there are many hermaphroditic gametophytes in the culture, sperm are immediately attracted to them and cluster tightly around the area of mature archegonia. Once attracted to the archegonial region, sperm do not appear to swim away in search of other adventures! Consequently, in a culture with many mature archegonia, the sperm swim freely only for a short period of time.

If you want to visualize freely swimming sperm for longer periods of time, male gametophytes should be removed from the culture and suspended in a drop of water or Sperm Release Buffer (SRB). Refer to directions in Chemical Attraction – C-Fern Sperm Chemotaxis for the SRB formula. If there are no hermaphroditic gametophytes are present, sperm may swim around for a very long period of time. Under optimum conditions (e.g. low temperature) sperm can swim for as long as two hours in SRB.