Limber Pine - Related Species

Related Species

Limber Pine - Pinus flexilis is a member of the white pine group, Pinus subgenus Strobus, and like all members of that group, the leaves ('needles') are in fascicles (bundles) of five, with a deciduous sheath. This distinguishes it from the Lodgepole Pine, with two needles per fascicle, and the bristlecone pines, which share five needles per fascicle but have a semi-persistent sheath.

Whitebark Pine—Pinus albicaulis

Distinguishing Limber Pine from the related Whitebark Pine (Pinus albicaulis), also a white pine, is very much more difficult, and can only easily be done by the cones. In Limber Pine, the cones are 6-centimetre (2.4 in) - 12-centimetre (4.7 in) long where the species overlap, green when immature, and open to release the seeds; the scales are not fragile. In Whitebark Pine, the cones are 4-centimetre (1.6 in) - 7-centimetre (2.8 in) long, dark purple when immature, and do not open on drying, but are fragile and are pulled apart by birds (see below) to release the seeds. A useful clue resulting is that Whitebark Pines almost never have intact old cones lying under them, whereas Limber Pines usually do.

Western White Pine—Pinus monticola

In the absence of cones, Limber Pine can also be hard to tell from Western White Pine (Pinus monticola) where they occur together in the northern Rockies and the Sierra Nevada east slope. The most useful clue here is that Limber Pine needles are entire (smooth when rubbed gently in both directions), whereas Western White Pine needles are finely serrated (feeling rough when rubbed gently from tip to base). Limber Pine needles are also usually shorter, 4-centimetre (1.6 in) - 7-centimetre (2.8 in) long, to Western White Pine's 5-centimetre (2.0 in) - 10-centimetre (3.9 in) (though note the overlap).