LABORATORY 1: EXERCISE IN BASIC TAXONOMY: CLASSIFICATION - NOMENCLATURE - IDENTIFICATION

If you would like to review the basics of Classification, Nomenclature, or Key-making, click on that topic. To review the all the basics of taxonomy, click HERE

A. CLASSIFICATION

STEP 1:

Determine the nature of your basic unit. Analyze bolt variation and find groups of bolts that have all characteristics in common. You have _____ basic units with _____ bolts per unit. Likewise, every individual flowering plant can be assigned to the basic unit of plant systematics, the SPECIES, although the analogy breaks down when we consider the nature of INTRA-SPECIFIC VARIATION in plants vs. bolts. Why?______________________________________

STEP 2:

You have now defined 15 "species" of bolts. Develop your bolt classification system by examining INTERSPECIFIC VARIATION-- look for KEY CHARACTERS, i.e., characteristics that are useful from a taxonomic point of view. Communication about taxonomy requires the association of verbal symbols (TERMS) with objects or characters. Plant identification (and success in BOTN 301) depends upon a good knowledge of flowering plant terminology. Working with bolts, however, requires the use of only two specialized terms: PILEUS and STIPE (see here for definition). The pileus is similar to the angiosperm flower in that it is rich in key characters.

Examine pileus variation among your bolt "species" and arrange them into related groups. How many groups do you have? _______
Classification systems employ a series of categories, from the most to the least inclusive. The taxonomic hierarchy of plant systematics is as follows:

Kingdom (most inclusive: all plants)
Division
Class
Order
Family
Genus
Species (least inclusive)
 
 
Each category of the hierarchy has its RANK and CIRCUMSCRIPTION. Rank defines the hierarchial position of the category (Ex: Family is at a higher rank than Genus). Circumscription, essentially an imaginary line around the taxon, is based on key characters and separates a given category (TAXON) from other categories (TAXA).

At what rank have you defined your related groups?____________________________

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B. NOMENCLATURE

Classification of your bolt "species" based on characteristics of the pileus probably resulted in the creation of three groups, each having five "species". Following the botanical hierarchy, we can assign these three taxa the rank of "genus".
Now we can begin to name all of our categories, beginning at the genus level:

GENUS	KEY CHARACTERISTICS (BASIS OF CIRCUMSCRIPTION)
Carriage	Pileus circular in outline, no terminal groove
Machine	Pileus circular in outline, has a terminal groove
Hexhead	Pileus hexagonal

You can now establish a nomenclatural system at the species level. Following the rules of botanical nomenclature, each SPECIES NAME must include the GENUS NAME (Carriage, Machine, or Hexhead) plus a SPECIFIC EPITHET. This complete name is known as the BINOMIAL. Establish binomials for your bolt "species" in the following manner:

Examine the five "species" of each bolt "genus" and complete the following data table. Provide each "species" with an epithet once the description of that taxon is complete. Make up your own epithets, or draw from the list of Latin epithets. The table will serve to fix your epithet to the taxon for which it is intended. The TYPE SPECIMEN (an herbarium sheet of the plant specimen chosen as the standard for a species) serves this function for plant nomenclature.

DATA TABLE (measurements in mm.)

GENUS	SP. EPITHET*	COLOR	PILEUS DIAM.	STIPE LGTH.	OTHER
Carriage	__________	__________	__________	__________	__________
Carriage	__________	__________	__________	__________	__________
Carriage	__________	__________	__________	__________	__________
Carriage	__________	__________	__________	__________	__________
Carriage	__________	__________	__________	__________	__________
Machine	__________	__________	__________	__________	__________
Machine	__________	__________	__________	__________	__________
Machine	__________	__________	__________	__________	__________
Machine	__________	__________	__________	__________	__________
Machine	__________	__________	__________	__________	__________
Hexhead	__________	___________	__________	__________	__________
Hexhead	__________	___________	__________	__________	__________
Hexhead	__________	___________	__________	__________	__________
Hexhead	__________	___________	__________	__________	__________
Hexhead	__________	___________	__________	__________	__________

*NOTE: specific epithets cannot be repeated within a genus.



C. IDENTIFICATION

Your classification and nomenclatural systems for the Stoveaceae are complete. Now you can put your work to practical use through the development of a DICHOTOMOUS KEY . The key will allow anyone to identify any individual member of the Stoveaceae to "genus" and "species" in your classification system.
Organize your key in such a way that the user is confronted with a series of COUPLETS, each offering two alternative choices. The choices, based on key characteristics of the bolt to be identified, should eventually lead to a species identification or determination. It may be helpful to start by separating the genera as shown below:

1. Pileus hexagonal, terminal surface mostly flat. . . . . . . Hexhead, go to _____
1. Pileus circular in outline, terminal surface mostly convex............................... 2

2(1) Upper surface of pileus smooth...............................Carriage, go to _____
2. Upper surface of pileus with central groove. . . . . . . . .Machine, go to _____

Now construct a key to all bolt "species". You may use the above key as a starting point, filling in the couplet numbers as you assign them. Contrasting characteristics can be found in your data table, although you are free to use any aspect of bolt morphology. Remember that the more concrete a characteristic is, the better basis for a couplet it makes. When your key is completed, run a few bolts through it to check for accuracy. Finally, use keys that have been produced by other teams. Compare methods of organization, key characters used, and relative efficiency. Also note the confusion that results from production of many names for the same object. This is a major reason for the establishment of an International Code of Botanical Nomenclature.

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**Notice that the bolt family is called the Stoveaceae and not the Boltaceae. Why? It is called the Stoveaceae because there used to be a type of bolt called a Stove bolt that is considered to be most typical of the family.



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last updated June 25, 2010