1. ecology a sporadic variant distinguished by a single or very few correlated characters, without a distinct distribution area, e.g., flower color, the variations from type being less, and considered of less importance, than those shown by varieties —note they may be phenotypes or genotypes 2. ecology the category subordinate in rank to that of variety within the hierarchy of plants 3. biometrics the degree and mode of taper of a tree or log —synonym stem form, stem taper, tree form This definition last updated 10/24/2008