Andrew Lewis wrote:

In 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 went to the new shopping centre on the King's Road in London near
Sloane Square and there is a big scented lime there. I did not notice
any honeydew on the pavement below it. Perhaps this species does not
have the problem of aphid infestation that makes the common lime so
unsuitable for street planting.

The limes to which you refer are Tilia (linden or basswood) and not
Citrus. You might be describing T. cordata, which has several
cultivars. The "International Book of Trees" (Hugh Johnson, Simon
and Schuster, 1973) describes this species: "And in mid-summer they
sweeten the air most mellifluously with the scent of their
flowers."

To identify the specific variety, you might inquire at a local
plant nursery or garden club. Or visit an arboretum or botanical
garden, where trees are generally labeled.

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening pages at http://www.rossde.com/garden/