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Showing results for tags 'pemphigus spyrothecae'.
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Hi there, First post for me and a call for assistance and opinions identifying Native Black Poplar (Populus nigra sbsp betulifolia). I found (what I think is) a big old pair (going on 2m DBH and 150 years old at a guess) residing on the banks of a brook on the lowlands outside Taunton, both lapsed pollards. Normally when working in the field I assume I'm looking at hybrid black poplar, as its so common in the areas I frequent, and usually I'm right on closer inspection. However this time, given the location, form, leaf shape and presence of the spiral gall (Pemphigus spyrothecae) I am leaning towards I.Ding as the rarer Native Black Poplar. What gives me pause for thought is the presence of the spiral gall . This has been flagged in a number of documents I've read as a key way to identify native black poplar with trees apparently exhibiting the gall on the vast majority of leaves. However, on my specimens the gall is present on more like 20-30% of the leaves which left me wondering if this was in fact some sort of back crossed hybrid. Confusingly I've also found evidence that the galls can occur on hybrid black as well although not often. I've included some pictures below (annoyingly the trees were on the opposite side of the brook,. on land I did not have access to otherwise I would have some closer pictures of live leaves). Suffice to say the leaf margins were not as deeply indented as hybrid black poplar but the leaf shape varied between triangular and ovoid diamond. Any thoughts would be much appreciated! Cheers, JP .
