224 Miscellaneous, 



origin of species, and on the changes of climate which the earth 

 has experienced in past periods. The Smithsonian Institution 

 has just issued a very interesting pamphlet on this subject 

 relating to the Trees of North America, from which we make the 

 following extracts. The first relates to the mode of collecting 

 specimens for purposes of accurate comparison.) 



" Collections of the leaves, fruits, bark, and wood of our native 

 trees are particularly desirable, and from as many localities as 

 possible, in order to determine both their range and abundance, 

 and also to decide those knotty points as to true specific distinc- 

 tions, which still perplex the most skilful botanists. The speci- 

 mens from each tree should be kept carefully together, and the 

 name of the locality and collector given in full. Without such 

 collections no information as to the large genera of oaks, hickories, 

 magnolias, and, in fact, most others, can be at all depended on or 

 made use of. Collections from the extreme corners of the United 

 States, and from any part of the western mountains, will be par- 

 ticularly useful in determining all these questions. A good way 

 of preserving a complete set from each species of tree is to obtain 

 two pieces of the thick bark of the trunk about a foot square, 

 taking care not to rub off the mosses or lichens, which are often 

 very characteristic of the tree. Other specimens of bark from the 

 branches, sufficient to show all its changes in appearance, and 

 twigs with leaves, flowers and fruits, may be pressed between the 

 trunk bark, with sufficient paper of any kind intervening, to 

 absorb all moisture. One change of this paper will usually be 

 sufficient, (especially if the bark is dry;) and fruits, if large and 

 hard, may be so fixed as to hang outside, wrapped in paper. 

 Particular care is necessary to prevent mixture of specimens. 

 Blocks of wood from the trunk and branches at various seasons 

 are also desirable for experimenting upon. 



Observations as to the relative abundance of each tree at the 

 various stations may be expressed numerically, thus : very rare, 1 ; 

 occasionally met with, 2; not uncommon, 3; common, 4; very 

 common, 5 ; abundant, 6, &c. ; using numbers up to 10, and 

 explaining them. Frequently several trees will be found so nearly 

 • alike in abundance as to require the same number. Notice should 

 also be made of the nature of the country and soil — whether 

 mountainous, rocky, gravelly, sandy, or swampy, which will help 

 to determine the limits of the natural regions. The geological 

 structure of the district is, however, of secondary importance. 



