Single-leaf Pinyon
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196822166
2008-03-08T18:33:50Z
Eubot
231599
Removed taxobox colour. See [[User:Eubot/Removing colours from taxoboxen]].
{{Taxobox
| name = Single-leaf Pinyon
| status = LR/lc
| image = Single-leaf_pinyon_2.jpg
| image_width = 240px
| image_caption = Single-leaf Pinyon (''Pinus monophylla'' subsp. ''monophylla'') leaves and immature cones
| regnum = [[Plant]]ae
| divisio = [[Pinophyta]]
| classis = [[Pinophyta|Pinopsida]]
| ordo = [[Pinales]]
| familia = [[Pinaceae]]
| genus = ''[[Pine|Pinus]]''
| subgenus = ''[[Pinus classification|Ducampopinus]]''
| species = '''''P. monophylla'''''
| binomial = ''Pinus monophylla''
| binomial_authority = [[John Torrey|Torr.]] & [[John C. Frémont|Frém.]]
}}
The '''Single-leaf Pinyon''' (''Pinus monophylla'') is a [[pine]] in the [[pinyon pine]] group, native to the [[United States]] and northwest [[Mexico]]. The range is in southernmost [[Idaho]], western [[Utah]], [[Arizona]], southwest [[New Mexico]], [[Nevada]], eastern and southern [[California]] and northern [[Baja California]]. It occurs at moderate altitudes from 1200-2300 m, rarely as low as 950 m and as high as 2900 m. It is widespread and often abundant in this region, forming extensive open woodlands, often mixed with [[juniper]]s.
[[Image:Single-leaf_pinyon_1.jpg|left|thumb|Isolated Single-leaf Pinyon in open [[Juniperus osteosperma|Utah Juniper]] woodland, [[Pah Rah Range]], Nevada]]
It is a small to medium size [[tree]], reaching 10-20 m tall and with a trunk diameter of up to 80 cm, rarely more. The bark is irregularly furrowed and scaly. The [[leaf|leaves]] ('needles') are, uniquely for a pine, usually single (not two or more in a fascicle, though trees with needles in pairs are found occasionally), stout, 4-6 cm long, and grey-green to strongly glaucous blue-green, with [[stomata]] over the whole needle surface (and on both inner and outer surfaces of paired needles). The [[conifer cone|cones]] are acute-globose, the largest of the true pinyons, 4.5-8 cm long and broad when closed, green at first, ripening yellow-buff when 18-20 months old, with only a small number of very thick scales, typically 8-20 fertile scales. The cones open to 6-9 cm broad when mature, holding the [[seed]]s on the scales after opening. The seeds are 11-16 mm long, with a thin shell, a white [[endosperm]], and a vestigial 1-2 mm 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 by burying them. Some of these stored seeds are not used and are able to grow into new trees. Indeed, Pinyon seeds will rarely germinate in the wild unless they are cached by jays or other animals.
There are three subspecies:
*''Pinus monophylla'' subsp. ''monophylla''. Most of the range, except for the areas below. Needles more stout, bright blue-green, with few resin canals. Cones 5.5-8 cm long, often longer than broad.
*''Pinus monophylla'' subsp. ''californiarum'' (D. K. Bailey) Zavarin. Southernmost Nevada, southwest through southeastern California (northwest only as far as the [[San Jacinto Mountains]]) to 29°N in northern Baja California. Needles less stout, gray-green, with few resin canals. Cones 4.5-6 cm long, broader than long.
*''Pinus monophylla'' subsp. ''fallax'' (E. L. Little) Zavarin. Slopes of the lower [[Colorado River (U.S.)|Colorado River]] valley and adjacent tributaries from [[St. George, Utah]] to the [[Hualapai Mountains]], and along the lower flank of the [[Mogollon Rim]] to [[Silver City, New Mexico]]. Needles less stout, gray-green, with numerous resin canals. Cones 4.5-6 cm long, broader than long.
It is most closely related to the [[Colorado Pinyon]], which [[Hybrid (biology)|hybridises]] with it (both subsps. ''monophylla'' and ''fallax'') occasionally where their ranges meet in western Arizona and Utah. It also (subsp. ''californiarum'') hybridises extensively with [[Parry Pinyon]].
An isolated population of trees in the [[New York Mountains]] of southeast [[California]] with needles mostly in pairs, previously thought to be Colorado Pinyons, have recently been shown to be a two-needled variant of Single-leaf Pinyon from chemical and genetic evidence. Occasional two-needled pinyons in northern [[Baja California]] are hybrids between Single-leaf Pinyon and Parry Pinyon.
===Uses and symbolism===
The edible seeds, [[pine nut]]s, are extensively collected throughout its range; in many areas, the seed harvest rights are owned by [[Indigenous peoples of the Americas|Native American]] tribes, for whom the species is of immense cultural and economic importance. During the mid nineteenth century many Pinyon groves were cut down to make [[charcoal]] for ore-processing, destroying the traditional lifestyle of the Native Americans who depended on them for food. When the [[railroad]]s penetrated these areas, imported [[coal]] supplanted locally-produced charcoal.
[[Image:Ship_chain_for_clearing.jpg|left|thumb|Anchor chain formerly used for clearing woodlands in western Nevada]]Following the resulting re-establishment of Pinyon woodlands, many [[rancher]]s became concerned that these woodlands provided decreased [[livestock]] [[Fodder|forage]]. Efforts to clear these woodlands, often using a surplus [[battleship]] chain dragged between two [[bulldozer]]s, peaked in the [[1950]]s, but were subsequently abandoned when no improved forage resulted. The destruction of large areas of Pinyon woodlands in the interests of [[mining]] and [[cattle]] ranching is seen by many as an act of major ecological and cultural vandalism. Single-leaf Pinyon is also occasionally planted as an ornamental tree and sometimes used as a [[christmas tree]]. It is rarely seen in [[nursery (horticulture) | nurseries]], because it is difficult to germinate.
The Single-leaf Pinyon is the [[List of U.S. state trees|official state tree]] of the state of [[Nevada]], USA.
==References and external links==
* {{IUCN2006|assessors=Conifer Specialist Group|year=1998|id=42381|title=Pinus monophylla|downloaded=12 May 2006}}
*Ronald M. Lanner, 1981. ''The Piñon Pine: A Natural and Cultural History''. University of Nevada Press. ISBN 0-87417-066-4.
*[http://www.pinetum.org/cones/PNDucampopinus.htm Photo of cones (scroll ¾-way down)]
*[http://www.conifers.org/pi/pin/monophylla.htm Gymnosperm Database: ''Pinus monophylla'']
*[http://plants.usda.gov/java/profile?symbol=PIMO USDA Plants Profile: ''Pinus monophylla'']
[[Category:Pinaceae|Pinyon, Single-leaf]]
[[Category:Trees of Arizona|Pinyon, Single-leaf]]
[[Category:Trees of California|Pinyon, Single-leaf]]
[[Category:Trees of Idaho|Pinyon, Single-leaf]]
[[Category:Trees of Nevada|Pinyon, Single-leaf]]
[[Category:Trees of Utah|Pinyon, Single-leaf]]
[[Category:Trees of Baja California|Pinyon, Single-leaf]]
[[Category:Trees of the Great Basin desert region|Pinyon, Single-leaf]]
[[Category:Edible nuts and seeds]]
[[de:Einblättrige Kiefer]]
[[fr:Pinus monophylla]]
[[pt:Pinus monophylla]]