beware of the cow mumble

When I was walking around the open-by-appointment garden, I spotted the hairy umbellifer that has been making itself rather too free in my garden, growing in some long grass.  I asked the gardener if he knew what it was.  He replied that he didn't know its proper name, but he always called it cow mumble, and when he was a boy he used to feed the leaves to his rabbits.

Chatting over lunch with my beekeeping friends, one of them rolled up her sleeve to demonstrate what looked like a nasty set of rather random oven burns.  We asked her what happened, and she said that she had been pulling up a weed in the garden, and sap from the stem dripped on her arm.  She didn't think anything more of it, but the next day, going out in the sun in a short-sleeved shirt, she felt a sharp pain in her arm, and discovered a bad case of blisters.  The plant sap had photosensitised her skin.  Her doctor has told her that she will have to keep the sun off that arm for two years.  I asked what the plant was, and she said that she didn't know its proper name, but that she always called it cow mumble, and when she was a child she used to feed the leaves to her rabbits.

Looking in Marjorie Blamey and Christopher Grey-Wilson's Illustrated Flora of Britain, although cow mumble doesn't appear in the index of common names, I think the plant concerned is Hogweed, Heracleum sphondylium, which makes it a close relative of the notorious Giant Hogweed.  I don't know if it is only the sap from the stems that is toxic, given the past popularity of the leaves as rabbit food, though I suppose the rabbits might have been OK as long as they didn't sit around with their mouths open after eating.  The book says that Hogweed is the commonest umbellifer flowering in late summer.  It is described thus: Stout medium to tall, rather bristly biennial or short-lived perennial, to 2.5m, stem hollow, ridged.   Leaves pinnate with often 5 broad, lobed and toothed segments, bristly; upper leaves with large inflated bases.  Flowers white, rarely pink, 5-10mm, in large umbels up to 15cm across with 12-25 rays...open woodland, banks and rough grassland.  That certainly sounds like the thing in my garden.  So if you come across cow mumble you should give the sap an extremely wide berth.