DE CANDOLLE'S PHYTOGRAPHY. 295 



(1) Hold fast to common and universally known names, 

 whether in Latin or in modern languages. JRadix, caulis, 

 folium^ Jfos, etc., with their vernacular equivalents, are not 

 to give place to new-fangled substitutes. This, he thinks, will 

 rid us of " such useless terms as caulome, ^^AyZZome, etc." 

 Now these terms, along with trichome, seem to us legitimate 

 and useful, as succinct expressions of a morphological idea ; 

 they are annoying only when pedantically ridden as hobbies 

 over ground on which they are not wanted. 



(2) Do not entertain the idea that a change in the mode 

 of considering or defining an organ requires a change of 

 name. Although Linnaeus did take the leaf -blade for the 

 leaf, and define it accordingly, that did not much hinder the 

 coming in of a truer view, involving merely a change of the 

 definition. But one may intimate that De CandoUe here 

 comes into conflict with another rule he insists on, namely, 

 that terms should have unmistakably one meaning. When 

 we say — as we ever shall — that leaves are ovate, we speak 

 according to the Linnsean definition ; when we say that their 

 insertion is alternate, we use the word in a more comprehen- 

 sive sense ; when we have occasion to declare that cotyledons, 

 bracts, petals, etc., are leaves, we use the word in the most 

 comprehensive sense. All this involves considerable ambi- 

 guity ; and the endeavor to keep the new wine in the old 

 bottles causes no little strain. It is borne because it has 

 been applied gradually. If Linnaeus had started with, or 

 even reached our ideas, we should happily have had a nomen- 

 clature to match. Now we must be content, for descriptive 

 purposes, to employ some words both in a restricted and in 

 a comprehensive sense, and let the context fix the sense, just 

 as it must in ordinary language. Technical precision is only 

 a matter of degree. But it is clear that the excellent rule 

 here laid down need not forbid the introduction of terms to 

 express our conceptions, such as rhizome, caulome., trichome., 

 and the like. Yet these are ill-chosen terms, except the last. 

 In particular, rhizoma has long ago been appropriated for 

 something which is not of root nature, but the contrary. 



(3) The third counsel is to change the name of an organ, 



