PINUS 



345 



Dry, sandy loam of the coastal plain, forming extensive forests almost to the 

 exclusion of other species ; rarely found along the borders of swamps in 

 low, wet soil. Southeastern Virginia to Tampa Bay, Florida ; westward 

 through the Gulf States to the Red River in Louisiana, and the Trinity 

 River in Texas; rarely more than 150 miles from the coast (Sargent). 



41. P. cubensis, Griseb. 



Slash Pine. Swamp Pine 



Transverse. Growth rings variable. Summer wood variable, dense or open, 

 the transition from the spring wood usually -very abrupt ; the tracheids 

 conspicuously rectangular, very uniform and regular, with small, round 

 cavities and very thick walls, or again strongly rounded, very unequal, 

 often much compressed, the general structure both open and dense. 

 Spring tracheids squarish or rounded, the walls rather thin. Resin 

 passages numerous, large, chiefly in the summer wood ; the epithelium 

 in 1-2, rarely 3, rows of rather thin-walled, usually much flattened, 

 resinous cells. Medullary rays prominent, very broad, i cell wide, 

 numerous, distant 2-8, rarely 12, rows of tracheids. 



Radial. Rays sparingly resinous ; the ray tracheids rather high, predominant 

 in the low rays, everywhere very strongly reticulated. Ray cells of two 

 kinds : ( i ) short-fusiform cells equal to about 4 spring tracheids ; the 

 terminal walls thin and entire, locally thickened or coarsely pitted ; the 

 upper and lower walls thin and much broken down, but more commonly 

 thicker and irregularly pitted, these two forms gradually merging so that 

 they are not readily separable, sometimes conterminous with and merging 

 into tracheids ; the lateral walls with variable, chiefly lenticular pits, 1-6, 

 chiefly about 2-4, per tracheid, in the summer wood reduced to slits or 

 becoming obsolete. Bordered pits in 1-2 rows, numerous, elliptical, in the 

 summer wood quickly reduced and finally obscure or wholly wanting. 

 Pits on the tangential walls of the summer wood wholly wanting. 



Tangential. Fusiform rays rather numerous, high, and narrow, the terminals 

 acute or prolonged and composed of very large, broadly oval paren- 

 chyma cells and very large, terminal tracheids ; the short, inflated por- 

 tion composed of thin-walled parenchyma cells much broken out. 

 Ordinary rays rather numerous, broad, medium, the cells chiefly broadly 

 oval ; composed of dominant parenchyma cells with chiefly terminal, 

 sparingly interspersed, often high, and narrow tracheids. 



A tree 24-30 m. high, with a trunk upwards of .90 m. in diameter. 

 Wood heavy, exceedingly hard, very strong, tough, coarse grained, compact, 

 and durable. 



Specific gravity 0.7504 



Percentage of ash residue 0.26 



Approximate relative fuel value 74-83 



Coefficient of elasticity in kilograms on millimeters . . . 1,577. 



Ultimate transverse strength in kilograms 500. 



Ultimate resistance to longitudinal crushing in kilograms 10,626. 



Resistance to indentation to 1.27 mm. in kilograms . . . 2,985. 

 (Sargent) 



