BOTANICAL GAZETTE. 131 



of the ensuing year to the examination of the principal herbaria, 

 which I need not here specify, in Scotland (where the important 

 one of Sir Wm. Hooker still remained), England. France, Switzer- 

 land and Germany, namely those which contained the specimens 

 upon which most of the then-published North American species 

 had been directly or indirectly founded, especially those ofLinnaeus 

 and Grronovius, of Walter, of Alton's Hortus Kewensis, Michaux, 

 Willdenow. Pursh, and the later ones of DeCandolle and Hooker. 



After my return the work made good progress; the remain- 

 ing half of the first volume was brought out in thespring oJ the 

 year 1840. and by t e spring of 1843 the 500 pages of the second 

 volume, mostly occupied by the vast order Compositge, bad been 

 issued. But meanwhile I had in my turn to assume professorial 

 duties and incident engagements, — with die result that, although 

 the study of North American plants was at no time pretermitted, 

 either by Dr. Torrey while he lived, or by myself, we were unable 

 to continue the publication during my associate's life-time; and it 

 was only recently, in the spring of 1878, that I succeeded in bring- 

 ing '.'lit, in a ch inged form, another instalment of the work', com- 

 pleting the Gamopetalce. 



[n the interval I bad made two year-long visits to Europe for 

 botanical investigation, the first partly relating to the botany of 

 the South Pacific, the secou 1 wholly in view of "the North Ameri- 

 can flora. And since the last publication still another visit — Hie 

 fourth and we may suppose the last — of the same character and 

 the same duration, has been successfully accomplished. 



The serious question, in which we are all concerned, arises, 

 whether this work can be carried through to .1 completion, and the 

 older parts (wholly out of print and out of date) re-elaborated — 1 

 will not say by my hands — but in my time, or soon enough to 

 render the whole a reasonably full and homogeneous representa- 

 tion of the North American flora, as knewn in this latter part of 

 the nineteenth century. And it brings us to consider why the 

 undertaking to which so much time has been devoted, should be so 

 slow of accomplishment. 



If this slowness is a constant wonder and disappojntm nt fco 

 most people interested in the matter, 1 can only add that it is 

 hardly less so to myself. It is a constant surprise — if one may so 

 say — that the work does not get on faster. 



Of course the undertaking his become more and more for- 

 midable with the enlargement of geographical boundaries and of 

 the number of species discovered. As to the increase in the num- 

 ber of species to be treated, we have by no means yet reached the 

 end. The area, that of our continent down to the Mexican line, 

 we trust is definitely fixed, at least for our day. And. sine 3 we 

 cannot be rid of the peninsula and keys of Florida, which entails 

 upon us a considerable number of tropical species, mostly belong- 

 ing to the West Inaies — the southern boundary is now as natural 

 a, one as we can have. 



