For routine observations, the presence of some contamination will not seriously interfere with gametophyte growth or development. Contamination by certain types of algae can be much more destructive since contamination can spread rapidly and infect other cultures. If algal contamination is observed it is best to isolate or destroy the cultures. Students should be carefully instructed in the proper ways of data collection, including a very thorough explanation of appropriate random sampling. The easiest way for most users to cultures sporophytes is to use a mini-terrarium constructed from a plastic drink bottle.
Full instruction are available on the mini-terrarium web page.
Swimming sperm are typically easily observed shortly after adding water to the cultures, but in a few moments they seem to be all gone. If water is added to a C-Fern culture, sperm are typically released 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. Consequently, in a culture with many mature archegonia, the sperm swim freely only for a short period of time. If there are no hermaphroditic gametophytes are present, sperm may swim for a very long period of time.