Editing Pinus quadrifolia (section)

==Description==
''Pinus quadrifolia'' is a small to medium size [[tree]], reaching {{convert|8|to|15|m|ft|abbr=on}} tall and with a trunk diameter of up to {{convert|40|cm|in|0|abbr=on}}, rarely more. The bark is thick, rough and scaly. The [[leaf|leaves]] (needles) are in fascicles of 4–5, moderately stout, {{convert|2.5|-|5.5|cm|in|frac=8|abbr=on}} long; glossy dark green with no [[stomata]] on the outer face, and a dense bright white band of stomata on the inner surfaces. The Parry pinyon begins to grow cones at around 10 to 20 years, and seed production is maximized at 50 or more years of age. The [[conifer cone|cones]] are globose, {{convert|4|-|5.5|cm|in|frac=8|abbr=on}} long and broad when closed, green at first, ripening yellow to orange-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|5|to|7|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=32|abbr=on}} long, with a thin shell, a white [[endosperm]], and a vestigial {{convert|1|-|2|mm|in|frac=32|abbr=on}} wing; they are dispersed by the [[pinyon jay]], which plucks the seeds out of the open cones. The jay, which uses the seeds as a food resource, stores many of the seeds for later use, and some of these stored seeds are not used and are able to grow into new trees. In addition to birds, rodents and other mammals can distribute its seeds.

===Hybrids===
The Parry pinyon frequently [[Hybrid (biology)|hybridises]] with [[Pinus monophylla|single-leaf pinyon]] (''P. monophylla'') where their ranges meet in southern California and northern Baja California. Hybrids are distinguished by intermediate features, with needles usually fascicles of 2–3 with some stomata on the outer surface. It has been suggested by some [[botanist]]s that the [[holotype]] specimen of ''P. quadrifolia'' is itself from a hybrid; presumed pure, non-hybrid specimens having been given the new name ''Pinus juarezensis'', the Juárez pinyon, after the [[Sierra de Juárez]] of northern Baja California. However, there is no proof that these specimens are genetically 'purer' than the original type specimen, and few botanists accept ''P. juarezensis'' as other than a synonym of ''P. quadrifolia''.

Despite the ease of hybridisation with single-leaf pinyon, Parry pinyon is genetically probably more closely related to the [[Pinus johannis|Johann's pinyon]] (''P. johannis'') and [[Pinus culminicola|Potosí pinyon]] (''P. culminicola''), despite being separated from them by well over {{convert|1000|km|mi|abbr=on}}.

=== Fire Ecology and Effects ===
The low density of organic material in areas where the Parry pinyon is found reduces the risk of fires spreading. However, due to low-hanging branches and thin bark, the Parry pinyon itself is susceptible to fire.<ref name=":0">{{Cite web |title=Pinus quadrifolia |url=https://www.fs.usda.gov/database/feis/plants/tree/pinqua/all.html |access-date=2022-10-21 |website=www.fs.usda.gov}}</ref> Larger Parry pinyons can survive fires of low to moderate heat, but younger pinyons can be wiped out by fires. The Parry pinyon does not possess the ability to resprout after a fire.<ref>{{Cite web |title=Pinus quadrifolia Woodland Alliance |url=https://vegetation.cnps.org/alliance/62 |access-date=2022-10-21}}</ref>