|The Morton Arboretum's Naturalist Certificate Program|
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|Local Flora I: Spring - 2001||
The Chicago region lies along the northeastern edge of the Tall Grass Prairie biome of the Midwest. The prevailing landscape at the time of settlement was open prairie. This was interspersed with poorly drained flatland. There were also small to large tracts of savannas dotted with mostly Bur and White Oak. The southern portion of the lake yielded high White Pine topped dunes backed by vast prairies and marshes. These gave way to swamps of mixed hardwoods east- and northwards, with cool forests of Beech and Sugar Maple (Swink & Wilhelm 1994).
Habitat (place of growth) offers a useful aid to identification. Only plants sharing similar needs and adaptations can occur together within communities or habitats. Splitting the habitats into wetlands, woodlands, grasslands and rapid-change sites is one of the ways of defining these somewhat nebulous and overlapping communities. Each of these divisions can be subdivided into various smaller subsets. For the purposes of this course we will focus loosely on two habitat types, woodlands and grasslands.
What's in a name?|
The classification of plants involves placing them in a series of categories or logical classes which have been ordered to show relationships to one another. The names and sequences constitute the taxonomic hierarchy. Any one of these groups, at any level may be referred to as a taxon (plural = taxa). Most of these taxa have standard endings except for genus and species.
The current system of nomenclature is based on the principle that each plant is given a two-element name or binomial. The first element is called the genus (e.g., Erythronium) and the second element is the specific epithet. (e.g., albidum). Together these make up the species name. Adding the species author (usually a standard abbreviation), in this case Thomas Nuttall, will complete the species citation: Erythronium albidum Nutt.
Why a scientific binomial rather than a common name? Because there is then a single valid, universally recognized name. A scientific name also has "information content" because the idea of relationship is inherent in a binomial. In other words, if you know the characters of one species that belongs to a genus, then you may predict with a high degree of confidence the characteristics of other species of the same genus, even though you may have never seen them!
Common names are widely used and are often simple and easy to remember. They may be descriptive and colorful but many plants have more than one common name, many common names are given to more than one plant, and many are confusing, e.g., Dogtooth Violet (Erythronium albidum), which is not a violet, but a member of the lily family (Liliaceae). Finally and perhaps the biggest problem for this flora course is the fact that many plants do not even have a common name.
For plant identification one needs to examine both the flowers and vegetative characters such as leaves. Flower characters are useful for identification at the family and genus level. Leaf and vegetative morphology is more variable, so it is more useful at the species level. Based on these characters, flowering plants have been assigned to two broad groups: the monocots and the dicots.
NCP Course Information
Participants are welcome to register for courses based on general interest; no prior course work is required. For those wishing to pursue a certificate, 13 - 15 courses must be completed. Registration for these classes takes place at the Field Museum.
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Department of Botany, The Field Museum
Chicago, IL 60605-2496
Jane and John Balaban
North Branch Restoration Project