i8 



The Pines 



sharp, calloused-tipped ; the leaves are rather thinly scattered along the twigs and 

 persist for four to five or even nine years. The staminate flowers are oval, 6 

 mm. long, the anthers dark red; pistillate flowers are about the same length and 

 oval, the scales somewhat thickened and rounded at the apex, sometimes with a 

 minute tip. The cones, reaching maturity by the second autumn, are nearly 

 globose, about 4 cm. long, very flat at the base, light brown and shining. The 

 scales are comparatively few; the exposed portion is very thick, transversely ridged 

 and narrowed into a four-sided knob with a large concave apex without any spine 

 or bristle. The middle scales only are fertile and much the largest, the others re- 

 main closed ; they are dull light red on the unexposed portions. The seed is ovoid, 

 12 mm. long, nearly cylindric and rounded at the base, yellowish above, dark red- 

 dish brown below; the wing is about 3 mm. wide, Hght reddish brown and adheres 

 to the cone-scales when the seed falls; endosperm sweet and resinous; cotyledons 

 7 to ID. 



The wood is soft, weak and brittle, close-grained and pale brown; its specific 

 gravity is about 0.64. It is quite durable and is useful for fencing, fuel, and char- 

 coal, and is sometimes sawed into boards. The seeds are very important as food 

 for the Indians and Mexicans, reaching some commercial importance. The tree 

 is doubtfully distinct as a species from Pinus monophylla. 



II. CHIHUAHUA PINE Pinus chihuahuana Engelmann 



This pine barely enters our area in southern New Mexico and Arizona, being 

 common southward in Mexico. It occurs at an altitude of 1800 to 2250 meters, 

 where it forms the lower fringe of the pine forests. Its maximum height, in our 



area, is 15 meters, with a trunk 

 diameter of 6 dm. It is character- 

 istic by its sparse foliage and is 

 also called Yellow pine and Chi- 

 huahua top-cone pine. 



The branches are somewhat 

 ascending, forming a narrow, 

 round-topped conic tree. The bark 

 sometimes becomes 4 cm. thick, is 

 deeply fissured into broad flat 

 ridges of a dark reddish to nearly 

 black color and covered by close 

 thin scales. The branch-buds 

 are ovoid, sharp-pointed, some- 

 times 16 mm. long, their scales 

 light brown and fringed. The 

 leaves are in fascicles of 3, their loose brown sheaths soon faUing away; they are 

 pale, glaucous, green, slender, 6 to 10 cm. long, the apex sharp, little calloused; 



Fig. 12. Chihuahua Pine. 



