xviii INTRODUCTION 



an article or a book using them may be translated into all 

 the modern languages. The word Quercus clears awa/ 

 difficulties. French, English, German hearers know what 

 trees are meant — or they know just where in books of their 

 own language to find them described. 



The abbreviation that follows a scientific name tells who 

 first gave the name. "Linn." is frequently noticed, for 

 Linnaeus is authority for thousands of plant names. 



Two sources of confusion make common names of trees 

 unreliable : the application of one name to several species, 

 and the application of several names to one species. To 

 illustrate the first : There are a dozen iron woods in iVmeri- 

 can forests. They belong, with two exceptions, to differ- 

 ent genera and to at least five different botanical families. 

 To illustrate the second: The familiar American elm is 

 known by at least seven local popular names. The bur 

 oak has seven. Many of these are applied to other species. 

 Three of the five native elms are called water elm; three 

 are called red elm; three are called rock elm. There are 

 seven scrub oaks. Only by mentioning the scientific 

 name can a wTiter indicate with exactness which species he 

 is talking about. The unscientific reader can go to the 

 botanical manual or cyclopedia and under this name find 

 the species described. 



In California grows a tree called by three popular 

 names: leatherwood, slippery elm, and silver oak. Its 

 name is Fremontia. It is as far removed from elms and 

 oaks as sheep are from cattle and horses. But the names 

 stick. It would be as easy to eradicate the trees, root and 

 branch, from a region as to persuade people to abandon 

 names they are accustomed to, though they may concede 

 that you have proved these names incorrect, or meaning- 



