Wednesday, May 13, 2015

Botany picture #201: Achillea chritmifolia

No energy left to write anything in the evenings these days, so I will just post a botany picture. I have recently gone through my photo collection to pick out representative examples of Asteraceae (sunflower family) to decorate a phylogenetic tree, and I came across this photo of Achillea chritmifolia that I took in 2010, presumably at the Botanic Garden of Zurich.

I am still as impressed now as I was then by the large number of small capitula making up the corymbose panicles of this species, because the species I had been most familiar with since childhood, Achillea millefolium, has a rather poorer capitulescence.

Undergrads at my old university often got confused between Achillea of the Asteraceae family and superficially similar members of the Apiaceae family, which in Germany are usually about the same size, have similarly divided leaves, and sport double umbels of nearly always white flowers. (The ones here in Australia are morphologically much more diverse.)

In oral exams we always had a bouquet of flowers on the table, and the first task for the student would have been to pick two or three, say what plant family they belong to, and explain why. I remember a case when I was co-examiner; the student confidently picked Achillea millefolium and started as follows: "this is an Apiaceae because it has double umbels, flowers with four free petals..." Around that point the main examiner interrupted her and suggested she take another look.

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