Dichotomous Key

A dichotomous key is a powerful tool for use in biology or any of the life sciences. It is also used in logic problems, physical sciences, and many other avenues. They are identified by having a choice of one of two options. Each selection will lead you to another pair of choices that ultimately leads to a final conclusion or organism identification.

They can be used in various fashions, from sorting playing cards
playing card key

to identifying trees (while this is not a true dichotomous key – there are more than two choices for some of the steps – it helps show the branching process).

For more practice, try the following site:


If you have a tree that you are trying to identify, dichotomous keys are a good way to figure out what species you are dealing with. If you have a tree that you are trying to identify, try using the following dichotomous key from the OSU website:


SOTM: January 2012

Alana Dietz – Botany

I feel pretty luck to have had this young lady twice, once in Biology and now in Botany. She is a great team player and asks good questions. She is always willing to work hard and shows interest in the subject. These traits combined with her effervescent personality will allow Alana to be successful as she continues through her high school years and beyond into her career of choice.