THE FLORA OF NORTH AMERICA. 255 



ously be hopeless. I need not say that our dependence, for 

 the actual elaboration, must largely be upon associates, upon 

 the few who have the training and the vast patience, and the 

 access to herbaria and libraries, requisite for this kind of 

 work, but above all upon my associate in the herbarium at 

 Cambridge, to whom, being present with us, I will not further 

 allude. 



Of course we rely, very much indeed, upon the continued 

 cooperation of all the cultivators of botany in the country ; 

 and it is gratifying to know that their number is increasing, 

 new ones not less zealous than the old, and better equipped, 

 are taking the place of those that have passed away, and some 

 of them extending their exploration over the remotest parts 

 of the land, and into districts where there is most to be dis- 

 covered. All can help on the work, and all are doing so, 

 by communication of specimens and of observations. Those 

 within the range of the published Manuals and Floras get 

 on — or should get on — with only occasional help from us. 

 They should send us notes and specimens to any amount ; but 

 they should not ask us to stop to examine and name their 

 plants, except in special cases, which we are always ready 

 enough to take up. Those who collect in regions as yet des- 

 titute of such advantages may claim more aid, and we take 

 great pains to render it : partly on our own account, that we 

 may assort their contributions into their proper places, partly 

 for the encouragement of such correspondents, who otherwise 

 would not know what they have obtained, and who naturally 

 like to know when they have made interesting discoveries. 



But the scattered and piecemeal study of plants is neither 

 very satisfactory nor safe. And it involves great loss of time, 

 besides interrupting that continuity and concentration of at- 

 tention which the proper study of any group of plants de- 

 mands. As respects the orders of plants which are yet to be 

 elaborated for the Flora, and as to plants which require criti- 

 cal study or minute examination, necessarily consuming much 

 time, it is better to defer their complete determination until 

 the groups to which they severally belong are regularly taken 

 in hand. 



