From Asa Gray [before 3 April 1858]1
– [Gives a list of 146 genera taken from A. Gray 1856, indicating those species in each genus that could be considered closely related. CD has added to the manuscript the number of close species in each genus.]2
Of course I suppose most of the above are truly & originally distinct; some are probably not; a few pretty surely not.3
List of close species taken from AG’s Manual of botany .
Please cite as
Darwin Correspondence Project, “Letter no. 2249,” accessed on 10 December 2016, http://www.darwinproject.ac.uk/DCP-LETT-2249