The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
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The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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Plant species maintain different levels of variation within and among populations, much of which is genetically determined. As such, variation in form below the taxonomic rank of species, called infraspecific variation, is widely recognized in plants. In contrast to zoological taxonomy, three categories have been applied to recognize this variation in plants. In order of decreasing taxonomic rank, these are: subspecies, variety, and forma. Additionally, the category of cultivar is used to recognize horticultural varieties not typically found in naturally occurring populations. The subspecies, which is the most inclusive of the three categories, is usually applied in recognition of population variation that is correlated with geography. By definition, populations of subspecies differ from other such populations. Furthermore, subspecies are expected to interbreed more freely than species, which may comprise two or more subspecies. The category of variety is similarly applied to recognize variation below the level of subspecies. Unfortunately, the two categories are not distinct, and application of the taxonomic rank of variety is more frequently encountered. Forma, the least-inclusive category, is applied to recognize minor infraspecific variation that is presumably due to variation at a single gene and, as such, may vary within populations. Flower color variants are typically recognized at this level.
Clines and Ecotypes; Cultivar; Species; Taxonomy.
Stuessy, Tod F. Case Studies in Plant Taxonomy: Exercises in Applied Pattern Recognition. New York: Columbia University Press, 1994.