The Dichotomous Key...
Is the cell diameter between 0.8 and 1.2 micron
( 1 )
or between 1.5 and 2.2 micron
( 2 )
...?
Both the average diameter and its range in micron should be
measured; it is important to note whether the diameter is greater
than 1 micron or less than 1 micron.
