One of the higher plants may be said to be dominant if it be more numerous in individuals and more widely diffused than the other plants of the same country, which live under nearly the same conditions.

A plant of this kind is not the less dominant because some conferva inhabiting the water or some parasitic fungus is infinitely more numerous in individuals, and more widely diffused.

But if the conferva or parasitic fungus exceeds its allies in the above respects, it will then be dominant within its own class.

If the plants inhabiting a country as described in any Flora, be divided into two equal masses, all those in the larger genera (i.