JaesunJ's picture


Observed: 5th June 2013 By: JaesunJJaesunJ’s reputation in Plants

Anyone with any ideas what the long-leaved, furry plant here is? There were distinct "teeth" or spines along the leaf edges. It has me stumped I am afraid. No doubt it will turn out to be something pretty common.

Species interactions

No interactions present.

Species with which Common Knapweed (Centaurea nigra) interacts


lavateraguy's picture

Knapweed was what I was thinking ...

... though it is rather nondescript at this stage. But what is meant by "teeth or spines along the leaf edges"?

I don't recall whether knapweed is ciliate (with hairs along the edges of the leaves), which is how I would interpret this photograph, but ciliate and spiny are not the same.

landgirl's picture


Even on highest magnification the edges of the leaves look hairy, not spiny. I'm going to a site where there should be lots of this tomorrow, I'll have a close look!

landgirl's picture


I checked today and this is definitely C. nigra. See http://www.ispot.org.uk/node/337776

JaesunJ's picture

The leaves were hairy, but

The leaves were hairy, but they also had very clear, sharp, apparantly defensive spines on the edges of the leaves, a bit like the thistles to which I understand Centaurea is related. Thistle-like spines is what I mean, along the edges of the leaves, fairly widely spaced out and stronger on the younger leaves.

landgirl's picture


Any chance they could have been the hydathodes? You can see them on my photo linked above. Hydathodes are glands that exude water.