OF NORTH AMERICA. 
5 
Trie woody structure and permanence over 
ground during Winter under a state of hyber- 
nation, with evergreen leaves or sleeping buds, 
might most properly distinguish this series of 
Vegetation, and Xylogy might be a better term 
to apply collectively to their knowledge than 
Dendrology and Thamnology. 
Every one of the Botanical Regions of North 
America is distinguished by peculiar Trees, 
Shrubs and Vines ; in fact they form the most 
prominent feature of each by their size and per- 
manence. See my botanical regions. 
Although so much attention appeared to be 
paid to these ornamental and useful produc- 
tions, it was only lately that the multitude of 
our Pines, Oaks, Willows, Poplars, Ash trees, 
Hicories, Vines, Roses &c have been ascer- 
tained : and it is a fact that many Genera are 
as yet little attended to or in utter confusion ; 
many species and varieties being overlooked or 
blended as were formerly those of Oaks, Ash 
trees before Bose Sl c: my own sp. of Rosa and 
Vitis , well distinguished by me, are neverthe- 
less invisible to some blind Botanists around 
me. I have been engaged for years in study- 
ing the fine Genus Prunas , now divided into 
Primus , Cerasus , Padus , Orospodias &,c, 
and instead of 20 I know 80 or 40 species of it. 
I have discovered and possess a crowd of N. 
sp. belonging to the Genera P rinos, Ilex , Spi- 
rea , Ceanothus , Rhamnus , Celtis , Yavia , 
Hydrangea , Viburnum , Caprifolium , Evo- 
nymus , Clematis &c. I have even some new 
Genera of shrubs to describe in this Sylva. 
The Genera Vaccinium and Andromeda , 
must be divided into many, and quite reformed, 
revised, corrected as to sections and species. 
