CONIFERS 



15 



brown. Bark on young trunks dark brown or almost black and deeply furrowed, 

 becoming on old trees l^'-2' thick and divided into large unequally shaped plates 

 separating on the 

 surface into thin 

 closely appressed 

 light cinnamon-red 

 scales. Wood light, 

 soft, not strong, 

 rather brittle, light 

 red or often yellow, 

 with thick lighter 

 yellow or white sap- 

 wood ; in Arizona 

 occasionally manu- 

 factured into coarse 

 lumber. 



Distribution . 

 High cool slopes on 

 the sides of canons of , 



the mountain ranges of southern Arizona at elevations between 6000 and 8000, 

 sometimes forming nearly pure forests ; more abundant and of its largest size on 

 the mountains of Sonora and Chihuahua. 



15. Pinus ponderosa, La-ws. Yellow Pine. Bull Pine. 



Leaves tufted at the ends of naked branches, in 2- or in 2 and 3-leaved clus- 

 ters, stout, dark yellow-green, marked by numerous rows of stomata on the 3 faces, 

 o'-ll' long, mostly deciduous during their third season. Flowers : staminate yel- 

 low; pistillate clustered or in pairs, dark red. Fruit oval, horizontal or slightly 

 declining, nearly sessile or short-stalked, 3'-6' long, often clustered, bright green or 

 purple when fully grown, becoming light reddish brown, with narrow scales much 



thickened at the apex and 

 armed with slender prickles, 

 mostly falling soon after 

 they open and discharge 

 their seeds, generally leav- 

 ing the lower scales attached 

 to the peduncle ; seeds 

 ovate, acute, compressed at 

 the apex, full and rounded 

 below, y long, with a thin 

 dark purple often mottled 

 shell, their wings usuallf 

 broadest below the middle, 

 gradually narrowed at the 

 oblique apex, I'-l^ long, 

 about V wide. 



A tree, sometimes loO- 

 230 high, with a massive stem 5-8 in diameter, short thick many-forked often 

 pendulous branches generally turned upward at the ends and forming a regidar 



