Dichotomous key

Module 2: Dichotomous Key BIOL F195 – 2020 Hufford

 

A.              Trees with woody stem, needle-like leaves, cones……………….…………Plant 1

B.              Herbaceous plants , non-woody stem

a.     Flowers white, whorled leaves with alternate arrangement on flowering stalk, star-shaped (stellate) hairs…………………………………………………………………………….Plant 2

a.     Flowers purple, elongated sepals with fine hairs, multiple yellow-green anthers, purple stigmas………………………………………………………………………………………..Plant 3

b.     Flowers apetalous, multiple combined anthers or stigmas, leaves pubescent….Plant 4

5 Comments

  1. Thanks Kris, this works well for separating the plants, but you should avoid trichotomies. So under B you could use another category: C- plants with petals, and C’ plants lacking petals, that way you could place plant 2 and 3 under C, and plant 4 under C’ and only use two-way choices.

  2. Chelsea Barnett

    This is a very clear and easy to understand dichotomous key, I wonder though if in this situation they need to be so detailed and you could make it shorter and less specific. Good job!

  3. Kris Hufford

    Good tip! How about?
    A. Trees with woody stem, needle-like leaves, cones……………….…………Plant 1
    B. Herbaceous plants , non-woody stem
    C. Plants with petals
    a. Flowers white, whorled leaves with alternate arrangement on flowering stalk, star-shaped (stellate) hairs…………………………………………………………………………….Plant 2
    a. Flowers purple, elongated sepals with fine hairs, multiple yellow-green anthers, purple stigmas………………………………………………………………………………………..Plant 3
    C’. Plants without petals
    b. Flowers apetalous, multiple combined anthers or stigmas, leaves pubescent….Plant 4

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