Origin of Species Variorum

in some slight degree modified, .. still inherit those advantages that enabled their parents to become dominant over their compatriots. In these remarks on predominance, it should be understood that reference is made only to those forms which come into competition with each other, and more especially to the members of the same genus or class having nearly similar habits of life. With respect to commonness or the number of individuals of any species, the comparison of course relates only to the members of the same group. A plant 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, not living under widely different conditions of life. Such a plant is not the less dominant in the sense here used, because some conferva inhabiting the water or some parasitic fungus is infinitely more numerous in individuals and more widely diffused; if one kind of conferva or parasitic fungus exceeded its allies in the above respects, it would be a dominant form within its own class.

Species of the Larger Genera in each Country vary more frequently than the Species of the Smaller Genera.

If the plants inhabiting a country and described in any Flora be divided into two equal masses, all those in the larger genera being placed on one side, and all those in the smaller genera on the other side, a somewhat larger number of the very common and much diffused or dominant species will be found on the side of the larger genera. This, again, might have been anticipated; for the mere fact of many species of the same genus inhabiting any country, shows that there is something in the organic or inorganic conditions of that country favourable to the genus; and, consequently, we might have expected to have found in the larger genera, or