Texas Pinyon

Taxobox
name = Texas Pinyon
status = LR/lc | status_system = IUCN2.3
regnum = Plantae
divisio = Pinophyta
classis = Pinopsida
ordo = Pinales
familia = Pinaceae
genus = "Pinus"
subgenus = "Ducampopinus"
species = "P. remota"
binomial = "Pinus remota"
binomial_authority = (Little) D. K. Bailey & F. G. Hawksworth

The Texas Pinyon or Papershell Pinyon ("Pinus remota") is a pine in the pinyon pine group, native to North America. The range is in western Texas, United States, on the south edge of the Edwards Plateau and the hills between Fort Stockton and Presidio, and in northeastern Mexico, mainly in Coahuila but also just into Chihuahua and Nuevo León. It occurs at low to moderate altitudes, from 450-700 m on the Edwards Plateau and from 1200-1800 m in the rest of its range. It is scarce, with small, scattered populations usually on dry, rocky sites and arroyos where bare rock lowers the likelihood of wildfire spreading easily.

It is a small tree or large shrub, reaching 3-10 m tall and with a trunk diameter of up to 40 cm. The bark is thick, rough and scaly. The leaves ('needles') are in mixed pairs and threes (mostly pairs), slender, 3-5 cm long, and dull gray-green, with stomata on both inner and outer surfaces. The cones are squat globose, 3-5 cm long and broad when closed, green at first, ripening yellow-buff when 18-20 months old, with only a small number of thin scales, with typically 5-12 fertile scales. The cones open to 4-6 cm broad when mature, holding the seeds on the scales after opening. The seeds are 10-12 mm long, with a very thin shell, a white endosperm, and a vestigial 1-2 mm wing; they are dispersed by the Western Scrub 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.

Texas Pinyon was previously included in Mexican Pinyon, only being discovered to be distinct in 1966 when US botanist Elbert L. Little noticed that the seed shells of some pinyons in Texas were very thin compared to those of some others. He treated it as a variety of Mexican Pinyon, "Pinus cembroides" var. "remota". Subsequent research found other differences, and it is now usually treated as a distinct species, probably more closely related to the Colorado Pinyon "P. edulis", which shares thin seed shells and needles mostly in pairs. Texas Pinyon differs from both Mexican and Colorado Pinyons in the very small, recessed umbo on the cone scales (larger and knob-like on other pinyons).

The edible seeds are occasionally collected like those of other pinyons, and sold as pine nuts; however, in its barren, dry habitat, infrequent and small crops are normal, reducing its economic value. It is occasionally planted as an ornamental tree, where its remarkable tolerance of drought and even semi-desert conditions makes it valuable in hot, dry areas.

References

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External links

* [http://www.pinetum.org/cones/PNDucampopinus.htm Photo of cones (scroll half-way down)]