PINE TREES OF ROCKY MOUNTAIN REGION. Ff 
LIMBER PINE. 
NAL Pinus flexilis James. 
COMMON NAME AND EARLY HISTORY. 
Pinus flexilis is generally known in its mountain habitat as “ white 
pine”; but as this name properly belongs to Pinus strobus of north- 
eastern United States, the common name “ limber pine,” coined from 
the tree’s technical name, flexilis, has been adopted. This name ap- 
propriately refers to the marked flexible quality of the twigs. 
Limber pine was found first in 1820 near timber-line at the base of 
Pike’s Peak, Colo., by Dr. Edwin James, a United States Army 
surgeon and naturalist attached to Stephen Harriman Long’s expedi- 
tion to the Rocky Mountains. Dr. James was also the first to name 
and describe this tree, his account of it being published in 1823. 
Since that time the botanical history of limber pine has been moder- 
ately free from confusion with related white pines of its range.? 
DISTINGUISHING CHARACTERISTICS. 
Pinus flexilis 1s a comparatively little-known species, doubtless 
because it grows chiefly in high places difficult of access. It is a low, 
thick-trunked, much-branched tree, from 25 to 50 feet in height, or 
sometimes 80 feet, with a short trunk from 12 to 30 inches in diam- 
eter; occasionally very old trees are from 34 to 4 feet in diameter. 
Young trees are peculiar for their regular distinct whorls of short, 
very tough branches, which stand out at right angles to the trunk 
and extend down to the ground. Middle-aged and old trees (from 
75 to 200 years old) are characterized by extremely long and slender 
branches, especially near the ground and at the top; the latter are 
often 16 or 18 feet long and droop gracefully at a sharp angle with 
the trunk. These branches appear to develop entirely at the expense 
of the trunk, which remains stunted. 
Large trunks have blackish or very dark-brown bark, which is 
from 14 to nearly 2 inches thick and deeply furrowed between the 
wide rectangular blocks; on trunks from 8 to 12 inches thick the bark 
is broken into small, thin, gray-brown plates. When separated, the 
scales expose a dull reddish inner bark. The thin, smooth bark of 
young pole-size trees and of branches is a bright whitish-gray, often 
1Dr. C. C. Parry is said to have been the first to introduce this pine into cultivation, 
plants having been raised in the Harvard Botanic Garden from seed he collected in Colo- 
rado in 1861. The‘tree is possibly not adapted to our eastern climate, for the trees 
raised from Dr. Parry’s seed attained a height of only about 5 feet in 35 years. Further 
planting of the tree at the Letchworth Park Forest and Arboretum, Wyoming County, 
N. Y., will later throw light upon this question. It appears to be better adapted to the 
elimate of England, where, according to Elwes and Henry (The Trees of Great Britain 
and Ireland, V, 1048, 1910), three trees in Kew Gardens, probably grown from Dr. 
Parry’s seed, had reached a height of 32 feet and about 11 inches in diameter in 1910. 
Other smaller trees planted in England are growing thriftily. 
