62 T O R R E Y A 



in a name, a rose by any other name would smell as sweet"" but in cases like 

 these, one is reminded of an expression used by one of the characters in that 

 intriguing comedy, "You can't take it with you" when he was expressing his 

 opinion of the dancing ability of another character in the play. 



In this part of the discussion I am rapidly approaching a category recently 

 discussed in the daily press. Under date of May 18, it is reported from 

 Raleigh, Xorth Carolina, that some years ago the Daughters of the American 

 Revolution planted, with elaborate ceremony, a little tree purported to be an 

 offspring of the '"Continental Elm"' at Cambridge, Massachusetts, under whicli 

 George AA'ashington is supposed to have taken command of the Continental 

 Army in 1775. They even kept a box of earth taken from around the roots of 

 the parent tree for use in christening the "elm" when it grew up. The little 

 "elm"' has grown up and is now blooming; but it is a cherry tree and not an 

 elm at all. Assuming that the young tree that was planted was provided by 

 some nurseryman this merely proves that nurserymen and horticulturists 

 can make mistakes just as botanists do, but is this any reason why a botanist 

 making a really serious studv of a plant problem should accept without ques- 

 tion as to its correctness, a commonly used but erroneous horticviltural name,. 

 or should determine what binomial he should use merely by looking up a 

 common name? 



One closing example, that of the investigator who had laborioush' dug up 

 and intensively studied the root tips of Tilia in one of our large collections, and 

 could not understand the discrepancies between the chromosome counts of the 

 root tips and of the branchlets taken from the same trees in a number of cases. 

 It was only after the study had been completed, but fortunately not published^ 

 that he learned that many of these species of Tilia were grafted, the roots 

 representing an entirely different species from the growing tree. Thus for cer- 

 tain types of investigations we cannot even trust the living plants without 

 knowing something about their history. 



I have above referred to the fact that during the many centuries Europe 

 was dependent on its own economy, its inhabitants utilized only a relatively 

 few plant species ; a few hundred important ones at most. As various parts of the 

 world were opened up within the few centuries following the expansion of 

 the European colonizing nations the number of species utilized rapidly 

 increased ; and this tempo of increase continues unabated. In 1853, Linnaeus 

 recognized 5,950 species of plants in all groups for the entire world, while he 

 and his immediate followers estimated that there might be as many as 10.000 

 species of plants, in all groups, in the world. The estimate had been increased 

 to 30,000 known species by 1820, and 50,000 indicated as probable for the entire 

 world. By the middle of the century the estimate of known species was 93,000. 



\Mthin the present century about 265.000 new binomials have been pub- 



