Photosensitization : causes?

[Roger Riordan]

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 
>graveolens).

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.


Roger Riordan.