404 



Dr Christison on the 



•[iSEss. mi. 



diioiis species, although not in all instances affecting the same 

 ones each year. In the Urst of these depressions no ever- 

 green species shared, unless Taxus haccata, to a very slight 

 degree, but in the second the Sequoia suffered almost to as 

 great a degree as in 1883. As this is the most remarkable 

 circumstance, I give the results in this species in detail — 



1887. — Looking only at class results, this depression seems 

 no worse than the two preceding ones, as far as the deciduous 

 trees are concerned. But a more minute investigation shows 

 that most of the better-tested species experienced a consider- 

 able decline, and that the class result is only saved from 

 being extremely low by the average of the less well-tested 

 species being high. In three of the better-tested species, 

 Tilia euro23cea, Acer Fseudo-Platanus, and Quercus Bohur, the 

 conclusions are obscured by the probable subjection of these 

 species to jjrolonged depression from the effects of the hard 

 winters 1879-80-81, but as the best trees in each suffered 

 severely, there can be little doubt tliat these species were 



