Amadan's picture

Another big Asteraceae at Woodwalton

Observed: 30th July 2013 By: AmadanAmadan’s reputation in PlantsAmadan’s reputation in PlantsAmadan’s reputation in PlantsAmadan’s reputation in Plants

Growing in damp areas, typically in clumps. Ignore the Marmalade Hoverfly - after being a.w.o.l. so far, they were everywhere today.

Species interactions

No interactions present.

Species with which Marsh Sow-Thistle (Sonchus palustris) interacts


landgirl's picture


...with S. palustris, because leaves don't look spiny enough for S. arvensis and glandular hairs are greenish. Woodwalton Fen is a known site for S. palustris.

Amadan's picture

"Woodwalton Fen is a known site for S. palustris."

I'm a little worried that once I discovered that, I was biased in my identification. What do you nice people suggest I check to confirm, please?

lavateraguy's picture

Streeter says ...

... rounded lobes and orange hairs for arvensis; pointed lobes and black hairs for palustris. For the latter Stace says "glandular hairy above with usually dark glands", and contrasts the leaf lobing - arvensis is less heterophyllous, being variably but typically shallowly lobed throughout, while palustris is deeply lobed below, and unlobed except for the basal auricles above.

On the grounds that it doesn't look like any arvensis that I've seen, I'd go for palustris (which I've never knowingly seen).

landgirl's picture


It's also about the sheer size of the thing - it was towering way above my head when I saw it. I haven't met S. arvensis that big!

Amadan's picture

A local botanist

Assures me it's palustris.

Update: also confirmed by reserve personnel.
It is a re-introduction of several years' standing.