Quantitative and experimental studies of the systematics of Arctostaphylos uva-ursi (Ericaceae) in North America

TitleQuantitative and experimental studies of the systematics of Arctostaphylos uva-ursi (Ericaceae) in North America
Publication TypeThesis
Year of Publication1983
AuthorsRosatti TJames
DegreeDoctor of Philosophy
Number of Pages362 pp.
UniversityUniversity of Michigan
CityAnn Arbor, MI
KeywordsVARIATION
Abstract

The following is an investigation of an important and widespread plant species which has been variously classified by different authors. No less that 7 infraspecific taxa have been proposed in North America and the taxonomy has been controversial. The results of this study bear not only on the systematics of the group involved, but on the conception and significance of infraspecific categories in plant classification as well. In conclusion, the present study has suggested that divergence does exist in this group, but at such low levels that to name them would require the establishment of three additional infraspecific categories, all of them below the rank of variety. Although such an action might be supportable on logical grounds, this process could at least theoretically continue, by application of the same reasoning, until every genotype in nature had its own name. Although such an extreme is preposterous and would clearly serve no purpose, it does point out that decisions must ultimately be made regarding the extent to which we should continue to recognize finer and finer levels of divergence by naming them. In the present case, where the same genotypes are apparently capable of assuming different, named phenotypes, that may even represent several potentially distinct evolutionary units, it appears that such a limit of categorization has been reached. In any event, it would serve no purpose to retain names for these variants whose corresponding identities are so flexible. The only category worth recognizing with a name in this group is at the specific level: Arctostaphylos uva-ursi, with considerable minor variation.