29T 



In examiniiift- the tigures obtained it is seen tliere are six species in 

 "O'hicli the spring wood traclieides are longer tliaji those of the summer, 

 Avhile seven species have the summer tracheides tlie longer. The species 

 in each group shoAV variations in hardness and strength, so that taking 

 the length of the tracheides as a factor by itself nothing can be deduced 

 in regard to the quality of the wood, but taliing the length and comparing 

 it with the width of the cells, and again comparing the width and the 

 thickness of walls together, and the amount of the spring and summer 

 wood, the strength can be determined within limits in each species. 



For Instance, in P. ponderosa scopulorum the spring tracheides are 129.6 

 times as long as they are wide, and the summer tracheides 164.4 times 

 their width, the thickness of their walls is not nearly as great as that of 

 many of the others, but when the thickness is compared with the width 

 of the cells, it is found to l>e fairly thick, and as about two-thirds of the 

 annual ring is summer wood, we have an explanation of the strength of 

 the wood. 



Taking any of these factors alone, it does not mean anything, as the 

 length of the elements may be vevy considerable, but the width may be 

 also; then, again, the elements may have rather thin walls, if the thick- 

 ness of the wall alone Avere considered. But Avhen the size of the cell 

 as a whole is taken into consideration along Avith the thickness, the pro- 

 portion of AvaU may be greater than the tigures representing the thick- 

 ness indicate. 



Contributions to the Flora of Indiana. 

 Stanley Coulter. 



The notes included in this contribution are based, partly, upon a crit- 

 ical study of certain species and partly upon reports and materials sub- 

 mitted by those interested in perfecting our knowledge of the flora of the 

 State. They are presented hi the h'ope that they may proA'e of interest 

 and value to the botanical Avorkers of the State. 

 Finns Strohiis L. White Pine. 



From Mr. C. F. Very, of A'eAA' Albany, I have received abundant speci- 

 mens of the leaves and cones of this species with the following notes. 

 The specimens are from trees planted by the father of Mr. Veiy some 

 seA'enty years ago. and one of them is about sixty feet in height, with a 



