Sacha writes

English people living in bits of France, btw. ;-) But I will correct that
info and pass it on to them outdoors. What rather surprised me was just
how huge the Prunus grouping is. Given that taxonomists seem to spend half
their time confusing the likes of me by changing the name of some perfectly
happy and innocent plant, how is it that Prunus is such a big LUMP of a
thing?!

The taxonomic system is an attempt to reflect the 'family tree' of the
plants involved. Therefore the assumption is that the various species of
Prunus are closely enough related to justify them all being in the same
genus (or, conversely, that they are not sufficiently different to
justify a split).

Or it could be that Prunus taxonmists tend to be 'lumpers' rather than
'splitters' ;-)

How many species does Prunus have? Thymus apparently has around 350
--
Kay