tree-logo.gif (7741 bytes) Plant Taxonomy (BIOL308)  -  Stephen G. Saupe, Ph.D.; Biology Department, College of St. Benedict/St. John's University, Collegeville, MN 56321;;

Keying Out Unknowns

    During the course you will be asked to use Gleason's & Cronquist's key to identify unknown specimens. We will use the format outlined below when we do formal identification work.

    Designate a section of your notebook for identifying unknowns. Obtain a copy of the Floral Analysis Worksheet.   Then, carefully examine your plant.  Make quick sketches of the entire plant including a leaf, flower (side and face view), stamen and pistil.  Don't spend an excessive amount of time doing your artwork - five minutes should suffice.  And don't hesitate to sketch other plant parts including fruits, leaf margins, or whatever.  Complete the Floral Analysis Worksheet and write the floral formula.    

    Now you are ready to begin your key work. Start in the key at the appropriate place; typically this would be the beginning of the key (Section 1 - General), but in some cases we will begin keying specimens in a particular family or genus. Record the title of the section that you are working in at the left-margin at the top of the page.  List the key steps and a brief description of the lead from each couplet as you proceed through the key. Indent each couplet as you proceed and use the prime (') to indicate the second lead of a couplet. The following is an example for keying out False Solomon's seal, Smilacina stellata, in Gleason & Cronquist (1991).  Once you have identified your plant, record the family, binomial, any synonyms, and the common name for this species on the Floral Analysis Worksheet.

Key Steps

Section 1

1'. Seed plants
    2'. Angiosperm
        3'. Rooting in soil
            4'. Without syndromes
                    9'   Bearing flowers
                            10.   Monocot . . . . . . .Section 6  

Section 6

1'. Perianth present
    19'. Flowers perfect
        24. Ovary superior
                25'. Ovary one
                        28'.   Flowers regular
                                30'. Perianth not differentiated
                                        34'. Stamens 6
                                                35'. Infl and perianth not white-wooly
                                                        36'. Leaves annual . . . . .Liliaceae


1'. Ovary superior
        6'. Flwr or infls terminal
                10'. Lvs alternate
                        12. Lvs cauline and alt.
                                13'. Stem not branched
                                        15. Tepals less than 2.5 cm
                                                16. Fls in raceme, fruit a berry
                                                        17'. Tepals 6 . . . . .. . . .Smilacina


1'. Fls in raceme
        2. Leaves 6 or more . . . . . . . . . . S. stellata (L.) Desf.



| Top | Plant Tax. Home | SGS Home | Disclaimer |

Last updated:  10/15/2007 / � Copyright by SG Saupe