In article , Franz Heymann notfranz.
writes

"Kay" wrote in message
...

It'd be a bit difficult, wouldn't it, with all the new varieties
being
developed. Addition of a new variety isn't necessarily a matter of
adding a new question at the end - it may mess up one of the
dichotomies
further up the key.

It would be quite acceptable to me if such a keyed book stopped short
of the varietal level. Nowadays nurseries think they have to attach a
pet name to every plant they sell.

Would it in fact be possible? Some of the varieties look different
enough to throw your identification, particularly half way down a key.
So although you might not be interested in the name of a variety, the
fact that it exists might be enough to throw the key completely.
--
Kay
"Do not insult the crocodile until you have crossed the river"