OF ORNAMENTAL TREES. 169 



grouped. Pollen contained in 2 cells, formed 

 in the scale that opens lengthwise. Female, 

 ovules 2. Strobile ovately conical in most 

 species. Carpels, or outer scales, thickened 

 at the tip, exceeding the bracteas or thin 

 outer scales in length, and concealing them ; 

 persistent. Leaves in groups of two, three, or 

 five, each group arising out of a scaly sheath. 

 (From London.) 



1. P. CEMBRA, Linnczus. Leaves in 5 7 s r 

 sometimes 3, with three ribs, the ribs serrated, 

 one of them green and shining, the other two 

 white and opaque. Buds white and without 

 resin. Cones about three inches long and 

 two and a half broad. Swiss pine. Native 

 of Switzerland and Siberia. 



Though a somewhat old and well-known 

 species, it has not become common amongst 

 us. 



I have seen no large specimens around 

 Philadelphia. It is one of the slowest grow- 

 ing kinds; yet when large, so very compact 

 and regularly conical, as to be much admired. 



The plants in our nurseries are imported 

 chiefly from England. 



2. P. EXCELSA, Lam bert. Leaves- very Iong 7 



15 



