18 BULLETIN 460, U. S. DEPARTMENT OF AGRICULTURE. 
ably due, in large measure, to the fact that quantities of the seed are 
collected for food and for sale as sweetmeats, while in localities 
where this pine is less abundant rodents and birds devour much of 
every crop, for shortly after the seeds have fallen it is often diffi- — 
cult to find a single perfect one. | 
LONGEVITY. 
The extreme age limit of Mexican pifon has not been determined. 
It grows very slowly throughout its life, attaining an age of possibly 
225 years. Trees from 7 to 10 inches in diameter are from 125 to 
185 years old. 
PINON; NUT PINE. 
Pinus edulis Engelmann. 
COMMON NAME AND EARLY HISTORY. 
This distinctly desert-foothill tree is rarely if ever distinguished 
by lay people from the single-leaf pine (Pinus monophylia), espe- 
cially where the two species are mingled. Sometimes the long-leafed 
and larger-coned forms of Pinus monophylla and the shorter-leafed, 
smaller-coned forms of P. edulis are spoken of as different 
“varieties”? of the pifon tree that yields the “pine nuts” which 
Indians and settlers gather for food. 
The history of the pinon is closely connected with that of the 
single-leaf pine and shows that there has been much difference of 
judgment, which obtains even at the present time, regarding their 
botanical relationship, particularly their claims to specific rank. | 
Single-leaf pine was found for the first time by Gen. John Charles © 
Frémont in 1844 in southern California and was described in 1845 
as a distinct species under the technical name Pinus monophylla 
Torrey. Similarly, the pifion, found first by Dr. Wislizenus in New 
Mexico in 1846, was botanically described in 1848 for the first. time 
as a distinct species under the name Pinus edulis Engelmann.* 
Forty-three years after this (1891) the latter tree was reduced to a 
variety of the single-leaf pine and designated as P. monophylla var. 
edulis M. E. Jones, while 16 years later (1907) it was again described 
as P. cembroides var. edulis Voss.2, Writers have differed also as to 
the proper botanical rank of the single-leaf pine; for in 1860, 15 
1It is not definitely known when Pinus edulis was first cultivated in England or in 
European gardens, where it is said to be growing. Elwes and Henry (Trees of Great © 
Britain and Ireland, V, 1058, 1919) state that small plants of it are growing in Kew 
Gardens. Prof. Sargent (S@lva, XI, 57, 1897), savs that it is hardy in eastern United 
States as far north as eastern Massachusetts. In 1886 the writer saw a small tree of 
this species, planted by William Saunders in the grounds of the Department of Agricul- 
ture about 1870. It died in 1888 after reaching a height of about 5 feet, apparently not 
being adapted to the soil and climatic conditions at Washington, where its growth had 
been exceedingly slow. 
2See footnote 4, page 16, 
