unit-steps

Updated: June 10, 2025

Such unit-steps may therefore be expected to become visible some time or other by artificial means. On the other hand, mutations as a rule make their appearance in groups, and there are many systematic species which on close inspection have been shown to be in reality composite assemblages. Roses and brambles, hawkweeds and willows are the best known examples.

Hugo de Vries - Species and Varieties, Their Origin by Mutation