10 PREFACE. 



Structure. There is, I believe, no sufficient work of this kind in 

 the English language, adapted to our needs, and available even to 

 our botanists and botanical teachers, — for whom the only recourse is 

 to a botanical library beyond the reach and means of most of these, 

 and certainly quite beyond the reach of those whose needs I have 

 here endeavored to supply, so far as I could, in this small volume. 

 The great difficulties of the undertaking have been to keep the book 

 within the proper compass, by a rigid exclusion of all extraneous 

 and unnecessary matter, and to determine what plants, both native 

 and exotic, are common enough to demand a place in it, or so 

 uncommon that they may be omitted. It is very unlikely that I can 

 have chosen wisely in all cases and for all parts of the country, 

 and in view of the different requirements of botanical students on 

 the one hand and of practical cultivators on the other, — the latter 

 commonly caring more for made varieties, races, and crosses, than 

 for species, which are the main objects of botanical study. But I 

 have here brought together, within less than 350 pages, brief and 

 plain botanical descriptions or notices of 2,650 species, belonging to 

 947 genera; and have constructed keys to the natural families, 

 and analyses of their contents, which I hope may enable students, who 

 have well studied the First Lessons, to find out the name, main char- 

 acters, and place of any of them which they will patiently examine 

 in blossom and, when practicable, in fruit also. If the book an- 

 swers its purpose reasonably well, its shortcomings as regards culti- 

 vated plants may be made up hereafter. As to the native plants 

 omitted, they are to be found, and may best be studied, in the Man- 

 ual of the Botany of the Northern United States, and in Chapman's 

 Flora of the Southern United States. 



This book is designed to be the companion of the First Lessons in 

 Botany, which serves as grammar and dictionary ; and the two may 

 be bound together into one compact volume, forming a comprehen- 

 sive School Botany. 



For the account of the Ferns and the allied families of Cryptoga- 

 mous Plants I have to record my indebtedness to Professor D. C. 

 Eaton of Yale College. These beautiful plants are now much cul- 

 tivated by amateurs ; and the means here so fully provided for 

 studying them will doubtless be appreciated. 



Harvard University Herbarium, 

 Cambridge, Massachusetts, August 29, 1868. 



