THE TRUE PINES. 193 



with which most writers confound it ; the cones of P. cembroides 

 have six or seven rows of scales, while those of P. Llaveana have 

 but three rows. 



It was first discovered in Mexico, and introduced by Hartweg, 

 who found it in the cold districts on the mountains of Orizaba, 

 near the village of Chichiquila, attaining a height of thirty feet 

 at an elevation of 10,000 feet above the sea. The tree is quite 

 hardy, and the seeds are eaten by the inhabitants of Orizaba. 



No. 28. PiNUS Chihuahuana, Wislizenus, the Chihuahua 



Pine. 



Leaves, in threes, very rarely in fours, finely toothed along 

 the edges, from two to three inches long, glaucous on the upper 

 part, and light green on the under one, very slightly striated 

 and fringed on the edges, buds scaly, pointed, and closely in- 

 laid. Sheaths, at first long, lacerated at the edges, but soon 

 falling off, and leaving the base of the leaves naked. Cones, 

 from one to one inch and a half long, and egg-shaped. Scales, 

 transversely oval, and without any mucro. 



This kind resembles Pinus inops in appearance, but is suffi- 

 ciently distinct in its smooth cones. It is found common on 

 the mountains of Chihuahua, in North Mexico, at an eleva- 

 tion of 7,000 feet above the sea, where it forms a tree from 

 thirty to thirty-five feet high. 



No. 29. Pinus Engelmanni, Car/iere, Engelraann's Pine. 

 Syn. Pinus macrophylla, Wislizenus. 



Leaves, in threes, but sometimes in fours, and very rarely in 

 fives, from thirteen to fifteen inches long, clustered at the ends 

 of the shoots, partially glaucous, keeled on all faces, and serru- 

 lated on the edges. Sheaths, at first long, scaly, jagged at the 

 ends, and one inch long, but afterwards much lacerated and 

 shorter. Cones, four inches long, and one inch and a half in 

 diameter, near the base. Scales, conical, and terminating on 

 the summit with a bent spiny mucro. 



