Pinus edulis

The piñon pine (''Pinus edulis'') is a small to medium size [[tree]], reaching {{convert|10|-|20|ft|order=flip}} tall and with a trunk diameter of up to {{convert|80|cm|in}}, rarely more. Its growth is "at an almost inconceivably slow rate" growing only 1.8 meters (6 ft) in one hundred years under good conditions.{{cite journal |last=Rehorn |first=John T. |date=Winter–Spring 1997 |title=The Gift |journal=American Forests |volume=103 |issue=1 |page=28 caption}} for an average growth of 18 millimeters (0.72 in) per year. The bark is irregularly furrowed and scaly. The [[leaves]] ('needles') are in pairs, moderately stout, {{convert|3|-|5.5|cm|in|frac=8|abbr=on}} long, and green, with [[stomata]] on both inner and outer surfaces but distinctly more on the inner surface forming a whitish band.

The piñon pine (''Pinus edulis'') is a small to medium size [[tree]], reaching {{convert|10|-|20|ft|order=flip}} tall and with a trunk diameter of up to {{convert|80|cm|in}}, rarely more. Its growth is "at an almost inconceivably slow rate" growing only 1.8 meters (6 ft) in one hundred years under good conditions.{{cite journal |last=Rehorn |first=John T. |date=Winter–Spring 1997 |title=The Gift |journal=American Forests |volume=103 |issue=1 |page=28 caption}} for an average growth of 18 millimeters (0.72 in) per year. The bark is irregularly furrowed and scaly. The [[leaves]] ('needles') are in pairs, moderately stout, {{convert|3|-|5.5|cm|in|frac=8|abbr=on}} long, and green, with [[stomata]] on both inner and outer surfaces but distinctly more on the inner surface forming a whitish band.

The [[conifer cone|cones]] are globose, {{convert|3|-|5|cm|in|frac=4|abbr=on}} long and broad when closed, green at first, ripening yellow-buff when 18–20 months old, with only a small number of thick scales, with typically 5–10 fertile scales. The cones open to {{convert|4|-|6|cm|in|frac=4|abbr=on}} broad when mature, holding the [[seed]]s on the scales after opening. The seeds are {{convert|10|-|14|mm|in|frac=16|abbr=on}} long, with a thin shell, a white [[endosperm]], and a vestigial {{convert|1|-|2|mm|in|frac=32|abbr=on}} wing.

The [[conifer cone|cones]] are globose, {{convert|3|-|5|cm|in|frac=4|abbr=on}} long and broad when closed, green at first, ripening yellow-buff when 18–20 months old, with only a small number of thick scales, with typically 5–10 fertile scales. The cones open to {{convert|4|-|6|cm|in|frac=4|abbr=on}} broad when mature, holding the [[seed]]s on the scales after opening. The seeds are {{convert|10|-|14|mm|in|frac=16|abbr=on}} long, with a thin shell, a white [[endosperm]], and a vestigial {{convert|1|-|2|mm|in|frac=32|abbr=on}} wing.{{Cite web |title=Pinus Edulis {{!}} Utah Valley University |url=https://www.uvu.edu/crfs/native-plants/pinus-edulis.html |access-date=2026-04-20 |website=www.uvu.edu |language=en}}

The species intermixes with Pinus monophylla sbsp. fallax (see description under ''[[Pinus monophylla]]'') for several hundred kilometers along the Mogollon Rim of central Arizona and the Grand Canyon resulting in trees with both single- and two-needled fascicles on each branch. The frequency of two-needled fascicles increases following wet years and decreases following dry years.{{cite journal |last1=Cole |first1=Ken |last2=Fisher |first2=Jessica |last3=Arundel |first3=Samantha |last4=Canella |first4=John |last5=Swift |first5=Sandra |date=2008 |title=Geographical and climatic limits of needle types of one- and two-needled pinyon pines |journal=Journal of Biogeography |volume=35 |issue=2 |pages=357–369 |doi=10.1111/j.1365-2699.2007.01786.x |pmc=3001037 |pmid=21188300|bibcode=2008JBiog..35..257C }} The internal anatomy of both these needle types are identical except for the number of needles in each fascicle suggesting that Little's 1968 designation {{cite journal |last1=Little |first1=Elbert |date=1968 |title=Two new pinyon varieties from Arizona |journal=Phytologia |volume=17 |pages=329–342}} of this tree as a variety of Pinus edulis is more likely than its subsequent designation as a subspecies of Pinus monophylla based entirely upon its single needle fascicle.

The species intermixes with Pinus monophylla sbsp. fallax (see description under ''[[Pinus monophylla]]'') for several hundred kilometers along the Mogollon Rim of central Arizona and the Grand Canyon resulting in trees with both single- and two-needled fascicles on each branch. The frequency of two-needled fascicles increases following wet years and decreases following dry years.{{cite journal |last1=Cole |first1=Ken |last2=Fisher |first2=Jessica |last3=Arundel |first3=Samantha |last4=Canella |first4=John |last5=Swift |first5=Sandra |date=2008 |title=Geographical and climatic limits of needle types of one- and two-needled pinyon pines |journal=Journal of Biogeography |volume=35 |issue=2 |pages=357–369 |doi=10.1111/j.1365-2699.2007.01786.x |pmc=3001037 |pmid=21188300|bibcode=2008JBiog..35..257C }} The internal anatomy of both these needle types are identical except for the number of needles in each fascicle suggesting that Little's 1968 designation {{cite journal |last1=Little |first1=Elbert |date=1968 |title=Two new pinyon varieties from Arizona |journal=Phytologia |volume=17 |pages=329–342}} of this tree as a variety of Pinus edulis is more likely than its subsequent designation as a subspecies of Pinus monophylla based entirely upon its single needle fascicle.