Is this not so?
If we had the number of genera strictly, or nearly strictly European, one could compare better with Asia and Southern America, etc.

But I dare say this is a Utopian wish, owing to difficulty of saying what genera to call mundane; nor have I my ideas at all clear on the subject, and I have expressed them even less clearly than I have them.
I am so very glad that you intend to work out the north range of the 321 European species; for it seems to me the by far most important element in their distribution.
And I am equally glad that you intend to work out range of species in regard to size of genera--i.e.number of species in genus.

I have been attempting to do this in a very few cases, but it is folly for any one but a botanist to attempt it.

I must think that De Candolle has fallen into error in attempting to do this for orders instead of for genera--for reasons with which I will not trouble you.
LETTER 332.

TO J.D.