and plants which reproduce asexually can cause terrible problems for the biological
sampler! Is a single sprig of moss an individual, or is the whole patch one individual?
In this case the best bet may be to assume that patches physically isolated
from each other are separate individuals, whereas those which are contiguous may well all
be the same individual. (This may not be true in all cases, but one has to make some
assumptions in order to sample. The assumption should be included in any write-up.)
Grasses which reproduce by sending out
runners and stolons can cover large areas with what looks like many different
individuals of the same species, although in fact they are all the same plant. New plants
will often arise where the runners or stolons touch the ground and root. If the runners
become detached or die off, the individual 'clone' plants remain as what appears to be
different individuals, although they are of the same genetic make-up. The collection of
'clones' of identical genetic make-up is called a 'genet'. The apparent 'individuals' of
the genet are called 'ramets'. The genets of some plant species may be hundreds, even
thousands of years old!
If you are faced with the problem of trying to determine numbers of
individuals of different grass species in a grassland, the best bet is to try and follow
runners or stolons so that you can identify all the seemingly separate plants which belong
to the same individual. As they are all interconnected, they should be treated as one
individual. Where connecting runners and stolons have been lost, then there is no way of
knowing whether the plants are different genetic individuals or ramets. They therefore
have to be treated as separate plants. In any case, as the interconnections have been
lost, they are to all intents and purposes different individuals, even if their genetic
make-up happens to be the same as the plant next door.