Introduction. xv 



make this statement here simply for the purpose of warning 

 beginners against depending too much upon descriptions, with- 

 out collateral knowledge, and against being hasty in their 

 decisions. It is hardly necessary to add that no person can 

 expect to become acquainted with the names of plants by the 

 use of books alone. There must be preliminary practical 

 knowledge to render the study of botanical works profitable. 

 As a rule we learn the names, and little more, of a great 

 many plants, and we often go on loading our brains with these 

 names until there is a break-down, because they are not asso- 

 ciated with any peculiar characters possessed by their owners, but 

 are simply based upon general appearance. Hence the need of a 

 book of reference to refresh the memory, and assist in deter- 

 mining the correct name of a plant. From what we have said 

 respecting the variability of plants, it naturally follows that all 

 descriptions are more or less comparative in their distinctions, 

 that is to say, without having any particular standard or 

 starting-point, we frequently employ the words small and 

 large, and many other terms, in describing plants of this or 

 that group, and therefore these terms are qualified to a certain 

 extent by the general characteristics of the plants under con- 

 sideration. It is far more hazardous to give dimensions with- 

 out allowing a wide margin for variation, than to limit the 

 description to distinguishing characteristics and relative size, 

 hairiness, etc. This course has been followed to a great extent 

 in the present work, and it is confidently believed that it will 

 meet with approval, and be of more service than disconnected, 

 though more complete descriptions. 



Botanical and Horticultural Nomenclature. With regard 

 to the nomenclature of plants, we have endeavoured to select 

 the names sanctioned by recognised authorities ; and in cases 

 where plants are more generally known under erroneous appel- 

 lations, these are given. In many instances plants possess 

 two or more names. This may have proceeded from different 

 botanists having published descriptions of the same plants 

 unknown to each other, or it may rest upon the views enter- 

 tained respecting the definition of a genus or species. Often- 

 times, however, the advance of knowledge has rendered it 

 necessary or desirable to change the name of a plant. Familiar 



