| When the trap
contents are brought in from the field Lycopodium
tablets are added so that pollen influx can be
calculated. The number of tablets added per sample
depends on the vegetation. The ratio between the number
of added Lycopodium and the number of pollen
counted in the pollen preparation must be such as to
ensure statistical reliability (Stockmarr, 1971, 1973).
In areas of low pollen producing vegetation 1 tablet may
be enough while in others areas 5 may still not produce
the desired ratio. For reasons of economy 5 tablets is
regarded as the maximum number which it is realistic to
add. A single tablet can be added directly to the trap
contents, with larger numbers of tablets participants may
wish to dissolve the Lycopodium tablets the day
before in distilled water (not in HCl since this produces
air bubbles inside the Lycopodium spores) and then
add this to the trap contents. |