Tuesday, March 17, 2009

Hitchcock and Cronquist


I must admit I knew nothing of these two names three weeks ago. It’s week two of the Plant ID course and we started using C. Leo Hitchcock (1902 – 1986) and Arthur Cronquist (1919-1992)’s Flora of the Pacific Northwest: An Illustrated Manual. The first edition was published in 1973 and is a condensation of their five-volume work Vascular Plants of the Pacific Northwest published between 1955 and 1969. As one reviewer noted about Flora – it “is not intended for pleasure reading.” I’ll second that. Though, it seems so deceptively easy, just answer the questions and you’ll identify the plant. I went off track so many times.

The strategy we used in class is that we first used a family key to identify the plant family, then a genus key and finally a species key. We worked with three plant families: Asteraceae (the sunflower family), Brassicaceae (the mustard family), and Lamiaceae (the mint family). In the class we are actually using the family key in Arnett’s Botanical Primer and then switching over to H&C for the genus and species keys. Included below is an example page from H&C for the mint family just to give an idea of how the dichotomous key works. H&C is laid out phylogenetically, that is, based on how plants evolved.
Example Page from Hitchcock and Cronquist
Tidbits: On the University of Washington campus Hitchcock has the botany building named after him. Also, there is a northwest plant image collection maintained by the University of Washington Herbarium. (I think I can finally appreciate what purpose a herbarium serves because this week I was looking for anything in bloom and with leaves that I could test my identification skills on. It’s hard because you can’t always get your hands on all of the plant parts you need any old time.)

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