The brief descriptions are merely for field use and in 
preliminary determinations of the species. For critical 
work the reader is advised to consult the magnificent 
work —Silva of North America by Professor Sargent. 
In conclusion let us cite some sentences uttered many 
years ago by Professor 1. F. Tausch: *‘ Unser Wéssen 
tst Stueckwerk, und unsere Weissagung tst Stueck- 
werk. Wenn aber kommen wird die Zett, wo wir in 
den elisaetschen Feldern botanisiren, so wird das 
Stueckwerk aufhoeren.” 
lvar Tidestrom. 
4 
