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35 Cards in this Set

  • Front
  • Back
2 valid reasons for changing a scientific name
1. Nomenclatural
2. Taxonomic
White Ash
Fraxinus americana
-have opposite,compound leaves (7 leaves)
-Oval shaped leaves
-The small flowers produce a winged fruit-narrow with a wind shaped like a narrow canoe paddle on one end
-Leaf bottom- white ash has white color on bottom of leaves
-used for baseball bats
Nomenclatural reason
• It is the necessity to bring the name in compliance with the rules of nomenclature in the Code.
• One rule is that of “priority”
1. Ex) the earliest valid name must be used
• A recent change of this type
-Yellow buckey
• It was from Aesculus octandra Marshall (published 1785), used in most literature through the 1980s, to A. flava Solander (published in 1778) (Meyer and Hardin 1987)
Taxonomic reason
• It occurs when the available evidence indicates the need for a change in classification.
Taxonomic reason example
1. Studies by Grant and Thompson (1975) and O’ Connell et al. (1988) indicated that the mountain paper birch is distinct from paper birch
2. So, it should be called Betula cordifolia Regel rather than B. papyrifera var. cordifolia (Regel) Fern.
• The study by Gillis (1971) showed a generic difference between the sumacs and their poisonous relatives, so poison-sumac, Rhus vernix L., was changed to Toxicodendron vernix (L.) Kuntze.
• There are four main sources for generic names
1. In commemoration
2. Descriptive
3. Fanciful, mythological, or poetic
4. Original common names in their native lands
Specific epithets have been derived from many sources
1. Descriptive of appearance or structure
2. Descriptive of habitat
3. Uses
4. Locality where first found
5. Resembling
6. Commenmorative
7. A noun, rather than adjective, and often an old Latin or Greek common name and sometimes old
generic name.
The endings of epithets follow__________
Latin grammar
Tree identification takes into account
1. Geographic area, Habitat
2. Form, Bark, Twig
3. Leaves, Taste, Aroma
4. Flowers, Fruits, Cones

Yet in many cases, tree species can be identified easily and correctly by analysis of less than a half
dozen characters.
Shortcuts to identification
• The easiest methods is to ask someone who knows
• Another popular method is to use illustrations in state or regional tree guides.
• Often a better approach is to use identification keys, available to genera and to species in some field
guides and more technical manuals of the plants of a state or region.
When attempting to identify an unknown trees
1. One should analyze the character states available, possibly overall form, bark, habitat, and locality
2. Then leaf and/ or twig, odor or taste, fruit or cone
3. Then flower and any other details.
The order of analysis is not important and is generally governed by _________ and ___________
conspicuousness and availability
Use _________ in a herbarium
-is a kind of trait
ex: bark or leaf shape
Character State
-is the particular form of that trait
ex: shaggy bark
The _______ is the common level of recognition, even in “folk botany” or “ethnobiological classifications”
throughout world.
Keys to genera
• Is usual group of plants, or animals
• Is most easily recognized as distinct
• based on general appearance
• Ex) pines, oaks, hickories, cherries, maples
The _______ is the most useful and practical unit for recognition and reason to begin your study of tree
identification with an artificial key to genera.
Using keys
• Using keys is one of the fastest and most popular methods of identifying unknowns.
A key is an analytical device
1. has dichotomies or a series of two brief contradictory descriptions
To use a key
1. You compare the characteristics of the unknown plant to both descriptions
2. One matching the plant either leads to a name for the plant or to another set of contrasting
3. You continue this pattern until, if all the correct choices have been made
4. You arrive at the correct name for the unknown.
When you key something out, always check
1. Description,
2. Illustration
3. Or herbarium specimen to verify your identification
Two basic types of keys
1. Synoptic key
2. Diagnostic key

These keys are usually “artificial” in that the sequence of the plants is based upon obvious similarities or “key characters” that don’t necessarily indicate evolutionary
Synoptic key
• It presents a condensed description of the more important technical characters that form the basis of their
phylogenetic arrangement.
• This type is seldom used for ordinary identification.
Diagnostic key
• It contains only the conspicuous characters that are most usable for identification.
• It is the most acceptable key
• It presents only two contrasting statements.
• Each pair of choices is called a couplet
• Each choice is called a lead.
• Keys may be written in either of two formats based on how the leads and couplets are arranged.
Indented key
• One or more couplets are indented and included under lead having the characters that are correct for
those couplets
• The contrasting lead is presented only after the indented couplet or couplets
Advantage of the indented key
• It is readily apparent which plants share certain characteristics
• The couplets don’t have to be numbered
• Numbers are sometimes used to make it easier to recognize the two leads of a couplet
• It is also easier to work backwards in an indented key to determine the characteristics of a particular
Disadvantages of the indented key
• It wastes space when the key is very long
• The two leads of a given couplet may be rather far apart.
Bracketed key
• It is the second type of format.
• In this format, the two leads of a couplet are kept together
• Each lead will either end in a plant name or the number of the couplet to which you would go next.
• Alternate couplets are indented for easier recognition
Advantages of bracketed key
1. The format of bracketed key is advantageous for very long key because the left margin is maintained
2. and there are little wasted space.
Disadvantages of bracketed key
1. It is nearly impossible to see similarities among the plants
2. It is harder to work backwards to obtain the characteristics of a plant
3. Backtracking is more difficult when a mistake has been made
4. The couplet must be numbered
5. There has to be number at the end of the lead that sends you to another couplet.
Using description to identify a tree
• The keys that follow are artificial, diagnostic keys to the genera.
• Each genus is defined only in terms of the species described.
• Some genera include species that are so different that they occur in different parts of the key.
– Such cases are indicated by “in part” (in pt.) placed after the generic name.
The keys are written to give you an opportunity to practice using keys in both formats,
– to help you learn the genera of trees and their morphological characteristics, and
– to group them by their obvious features that make them easier for you to remember.
– The more you use keys, the more proficient you will become.
The abbreviations used in the keys are:
– if., leaf; lvs.,leaves; lfts., leaflets;
– fls., flowers; frt., fruit.