THE KNOB CONE PINE.
P. attenuata, Lemm.
The knob-cone pine inhabits the Coast Ranges from the San Bernardino Mountains northward on the western slopes of the Sierra Nevada and Cascade Mountains, into southwestern Oregon, where it forms pure forests over large areas, its altitude limit being four thousand feet. It is a tall slim tree of the hot dry fire-swept foot hills, and it comes again with absolute certainty after forest fires. The clustered cones, three to six inches long, are amazingly hard and do not open at maturity, but wait for the death of the tree. Leaves three to seven inches long, in clusters of three, firm, rigid, pale yellow or bluish green, cover the tree with a sparse thin foliage-mass; but the branches, new and old, are covered with cones, many of which are being swallowed up by the growth of wood on trunk and limb. Thirty or forty years these
cones may hang, their seeds never released and never losing their vitality, until fire destroys the tree. Then the scales open and the winged seeds are scattered broadcast. They germinate and cover the deforested slopes with a crop of knob-cone pine saplings that soon claim all stand ing room and cover the scars of fire completely.