222. PlNUS ATTENUATA KNOB-CONE PlNE. 49 



PHYSICAL PROPERTIES. Wood rather soft and light, not strong, 

 quite resinous and with conspicuous resin-ducts. It is of a light 

 yellowish-brown color, often tinted with red and abundant lighter 

 sap-wood. Specific Gravity, 0.3499; Percentage of Ash, 0.33; 

 Relative Approximate Fuel Value, 0.3487; Coefficient of Elasticity, 

 4-2 s 70; Modulus of Rupture, 409; Resistance to Longitudinal Pres- 

 ?<"/'<:, 263; Resistance to Indentation, 86; Weight of a Cubic Foot in 

 Pounds, 21.81. 



USES. Amid the wealth of better woods of the Pacific slope little 

 use is made of this inferior timber save for fuel. 



MEDICINAL PROPERTIES are doubtless only those common to the 

 genus and noted of the P. palustris, Part V, p. 52. 



NOTE. In considering this tree we cannot refrain from wondering 

 what may be Nature's plan in keeping its seeds sealed so long, often 

 for a half century or more in its closed cones. Many of them are not 

 liberated during the lifetime of the tree, and when 'the cones become 

 wholly enveloped by the wood of the trunk it is not until the decay 

 of the trunk even that they are finally liberated, and, strangely, after 

 this long period of concealment they have been found to be fertile, 

 whereas the seeds of the deciduous-cone pines scarcely retain their 

 fertility it is said for more than two years. 



Many of the seeds of this species never have an opportunity to 

 germinate on account of the larvae of insects which infest the cones 

 and eat them. These grubs in the cones are dainty morsels for the 

 wood-peckers and hence it is that many of the cones have large holes 

 drilled into them by these hard-working birds. 



GENUS TSUGA, CARRI^RE. 



Leaves petiolate and articulated on permanent bases, flat in most species, 

 appearing two-ranked, whitened-beneath, with a single dorsal resin-duct, ever- 

 green. Flowers in early summer, monoecious ; the sterile sub-globose 

 clusters of stamens from the axils of the leaves of the previous year, the stipes 

 surrounded by numerous bud-scales ; anthers tipped with a short spur or knob 

 and cells opening transversely by a continuous slit ; fertile aments terminal on 

 the branchlets of the previous year, erect, bracts somewhat shorter than the 

 scales. Fruit, pendulous cones maturing the first year ; scales thin and persistent 

 on the axis ; bracts short, inclosed ; seeds with resin vesicles on the surface and 

 wing finally breaking oft' ; cotyledons three-five or six. 



Genus consists of trees of few species with slender and often drooping terminal 

 branchlets. Tsuga is the Japanese name of one of the representatives of the 

 genus. 



