Fireweed Pollen

This is a fireweed pollen grain. The size of the largest enclosed circle is [1], 53.6um. The size of the smallest enclosing circle is [2], 94.2um. The longest dimension is [3], 91.9um. [4], 72.6um, is the Martin's diameter and one of the Ferret's diameters. These are five different "sizes" of this pollen grain. There are many other sizes that could be calculated for this particle.