This website seems to have the answer
http://www.malvaceae.info/Genera/Tilia/Britain.html
The 5 commonly planted limes in England
1 Tilia tormentosa scented
2 Tilia × euchlora suffers less from aphids
3 Tilia × vulgaris is a hybrid between 4 Tilia platyphyllos and 5
Tilia cordata

pamfree (Zemedelec) wrote in message ...
n England now it is the time of year that some lime trees have their
wonderful scent. Only some though, which makes me think that it may be
a different species that has the scent from the common lime. These
trees seem to have a darker leaf color than the common lime.

I assume you mean lime as in linden, the symbol of Czechoslovakia. I've never
seen sap under them, but they do attract a lot of bees for the nectar.
zemedelec