rwhitehead at cix.compulink.co.uk ("Roger Whitehead") wrote:
>>>> This phenomenon is also widely known in N Europe. (Scandinavia). The
>> culprit there is Heracleum pubescens & H. sphondylium. (Apiaceae).
>>Several of the umbelliferae offend in this respect. ........
> So, too, do various Citrus species, Scorpion Vetch
>(Coronilla spp.), Fig (Ficus carica) and, of course, Rue (Ruta
And, of course, Rhus. The ornamental varieties are bad - I got a burn
on my arm once, as bad as if I had touched it against my motorbike
exhaust, when I brushed against one while cutting grass with a motor
scythe, but the North American Poison Ivy (also a Rhus) is diabolical.