176 Trees and Shrubs of Massachusetts. 



fully interesting and instructivp, is something still greater. 

 In these respects, the report most happily coincides with the 

 practically scientific report on " Insects injurious to vegeta- 

 tion," prepared by Dr. Harris, itself also a State document, 

 and connected with the general subject of the State survey. 

 Mr. Emerson, in his letter to Governor Briggs, tells us that 



" The accompanying Report concludes the work of the Commission- 

 ers on the Zoological and Botanical Survey of the State. It has heen 

 prepared with especial reference to the instructions of Gov. Everett, accom- 

 panying his commission, and directing the Commissioners ' to keep care- 

 fully in view the economical relations of every subject of their inquiry.' 

 I trust it may do something ' to promote the agricultural benefit of the Com- 

 monwealth,' by leading citizens who are land-owners to a consideration of 

 the importance of continuing, improving, and enlarging the forests of the 

 State. 



" It is due to the Legislature, and to yourself, that I should make some 

 apology for the tardy appearance of my Report. It is well known to your 

 Excellency, that ever since the commission was issued, in 1837, I have been 

 occupied, for ten months of every year, in a pursuit which left me no leisure 

 for the Survey, and little for reading, on subjects connected with it. I have, 

 therefore, been able to give to it only the summer vacation, and of that a con- 

 siderable portion has, every year, been necessarily taken up with other 

 things. Under these circumstances, it was hardly possible for me to give 

 to the Survey the attention it deserved, and let my Report appear at an 

 earlier period." p. 1. 



We hinted at the method of arrangement : and of the facil- 

 ity aiforded to the reader in making the treatise of practical 

 value : 



" In order that this Report should answer the ends for which the Survey 

 was ordered, the descriptions of the Trees and Shrubs are arranged accord- 

 ing to the Natural System. This has been done, not from undervaluing 

 the artificial system of Linnaus, which must still continue of use in aiding 

 to find the name of a plant and its place in the Natural System, but from a 

 conviction of the incomparably greater value of the latter. The artificial 

 system is based essentially on distinctions drawn from the stamens and pistils 

 alone. The Natural System, on the contrary, takes into consideration not 

 one part only, but every part and whatever relates to it, — the seed, from the 

 development of its embryo to its germination, the growth, formation and 

 arrangement of the wood, bark, buds and leaves, and the flower and fruit. 

 It is found that plants which resemble each other in the external forms of 

 their more essential parts, have a similar resemblance in properties and 



