ET. 66.] TO A, DE CANDOLLE, 669 
plimentary to American ladies, and as you are such 
an excellent judge, | must even give you the oppor- 
tunity of extending your range of instances, 
But please do not give our young friends the op- 
portunity of callmg upon you, unless it quite suits 
you. 
By the time this reaches you, Dr. Hooker will be 
on the way to us, we expect, and we are looking to 
have a great run together over the Rocky Mountains, 
and perhaps across the Continent. Wherever we may 
be, you may believe me, 
Always yours cordially, Asa GRAY. 
TO A. DE CANDOLLE. 
CAMBRIDGE, June 4, 1877. 
My pear Dr Canpo._e: . . . I meant to have a 
good portion of my ‘“¢ Synoptical Flora of North Amer- 
ica” to send you this summer; but it will not be 
quite ready at the time I expected, and I am now 
likely not to have this summer for writing, but rather 
for observation over a considerable range of country. 
Dr. Hooker, it seems now almost certain, is coming 
over in a month from now. Dr. Hayden has invited 
him and me to join his expedition of exploration this 
year, or rather to make a survey of much of his ground 
in the Rocky Mountains; and it is possible we may 
even reach California. I am rather old for this work, 
but judging from last year, I may well endure - 
enjoy it. Would that you could join us! 
We are in essential accord as to subgenus and its 
nomenclature. Your letter to Cogniaux Devnseen and 
decides —as I had done for myself — the questions 
propounded. You will see I follow it out consistently 
in my part of botany of California, while Watson was 
