122 TRANS. OF THE ACAD. OF SCIENCE. 



New Mexican nut-pine, Pin/us edulis, of an irregular oval 

 form, 4-5 lines long, and possess similar edible qualities. In 

 addition to other peculiarities of this pine, may be noticed its 

 slowness of growth ; thus on a small trunk of 7| inches in 

 diameter, there were 232 annual rings. Its wood is soft, of 

 fine texture; the heart wood inclined to a yellowish cast. The 

 flexibility of its branches, on which Dr. James founded its 

 specific name, is partly due to the thickness of the elastic bark 

 of the smaller twigs. The bark of the trunk is of a dark red- 

 dish-gray color, considerably furrowed, and about equal in 

 thickness to that of our common white pine. The average 

 height of full-grown trees is from 40 to 50 feet; they have a 

 rounded outline, are generally low branched, and spreading; 

 in the largest specimens observed, the trunk, a short distance 

 from the surface of the ground, had a diameter of two feet 

 and upwards. 



The vertical range of this species, as observed between 

 latitude 38° and 40° W., is from 7,000 to 11,000 feet above the 

 sea. It rarely occurs in large bodies of timber, but is mostly 

 of scattered growth, being associated, at its lowest range, with 

 Pinus ponderosa undPiuus contorta, and at its upper limits 

 with Pinus aristata and Abies Engelmanni. Besides Pinus 

 Jiexilis, which alone seems to have particularly attracted the 

 attention of Dr. James, he mentions, in a cursory way, the oc- 

 currence of Abies balsamea, A. Canadensis, A. alba, A. nigra, 

 and A. rubra, these being the then recognized representatives 

 of the fir tribe in eastern North America. In this enumera- 

 tion, the very common error of confounding analogous species 

 was committed; an error to which those who simply observe, 

 and do not collect, specimens, are quite apt to fall into. It is 

 sufficient to state, in this connexion, that nut a single one of 

 these species is recognized at present as occurring in this part 

 of the Rocky Mountains ; in fact, most of the species there 

 met with, were, at that early day, unknown to science. Under 

 the names of Abies nigra and A. rubra, there is little doubt 

 that Dr. James had in view a very puzzling Rocky Mountain 

 speeies, which, in imperfect material, has frequently turned up 

 in collections from this region, as being usually classed under 

 the names of A. alba or A. nigra. My attention having been 

 particularly directed to this species by Dr. Engelmann, I be- 

 came soon satisfied, in pursuing the investigation, that this 

 was in fact a single undescribed species, appearing under dif- 

 ferent forms according to soil, altitude and exposure; to 

 which, accordingly, I have ventured to affix the name of its 

 actual discoverer, calling it Abies Engelmanni. 



I continue the narrative of our ascent. On reaching an 

 elevation of about 9,000 feet, the contracted valley, up which 

 we were travelling, spread out into more free stretches, being 

 on a level with the plateau of the first range of foot hills. 



