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The Histological Difference Between Pinus Taeda and 

 Pinus Palustris. 



By Katherine Golden Bitting. 



Though the structure of the wood of a tree will show considerable 

 variation due to environment and conditions of growth, the variation will 

 be manifest in the amount of wood formed, and the size of the cells. The 

 characteristics which distinguish the particular wood remain constant, no 

 matter what the external conditions may be, so that it is always possible 

 to distinguish the wood of any species by the use of the microscope. It 

 is not always possible to distinguish woods macroscopically, even by expert 

 lumber men. This is particularly true of Coniferous woods, which are 

 composed of only one form of element, the tracheides. 



The close macroscopical resemblance of many Conifers, coupled with 

 the variety of local names possessed by nearly every species, has caused 

 much confusion in the lumber business. At present when a certain lumber 

 is specified in a contract, many times the only guarantee that the contract 

 will be properly filled will be the resemblance to the lumber named, along 

 with information as to the locality from which it was shipped, the latter 

 being the more reliable, if it be known to furnish pure groups. 



Two of the hardwood Conifers which are confounded are Pinus taeda 

 and Pinus palustris, or as they are more commonly known, Loblolly and 

 Longleaf pine. In addition to these Loblolly has twenty-two other common 

 names, and Longleaf twenty-seven, three of which are common to both. 



Pinus taeda is of wide distribution, due to its adaptability to grow in 

 different soils, consequently it shows considerable variation in its annual 

 growth in both height and diameter. The best lumber is obtained from 

 trees grown in mixed forests on well drained and fertile soil. These trees 

 give the gieatest growth in height, and a slower growth in diameter, both 

 varying with the age of the tree. The zones of the spring and summer 

 wood in the annual ring are nearly equal in extent, the spring wood shad- 

 ing gradually into the summer wood. In the gross, the zones are fairly 

 distinct, but under the microscope it is difficult to define their proximate 

 limit, as seen in the transverse and radial sections. The tracheides in 



