''Pinus culminicola'', commonly known as Potosí pinyon or Potosí Piñón, is a

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family (biology), family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanic ...

in the

pinyon pine The pinyon or piñon pine group grows in southwestern North America, especially in New Mexico, Arizona, and Utah. The trees yield edible nuts, which are a staple food of Native Americans, and widely eaten as a snack and as an ingredient in ...

group, native and

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to northeast

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

. The range is highly localised, confined to a small area of high summits in the northern

Sierra Madre Oriental The Sierra Madre Oriental () is a mountain range in northeastern Mexico. The Sierra Madre Oriental is part of the American Cordillera, a chain of mountain ranges (cordillera) that consists of an almost continuous sequence of mountain ranges that f ...

Coahuila Coahuila (), formally Coahuila de Zaragoza (), officially the Free and Sovereign State of Coahuila de Zaragoza ( es, Estado Libre y Soberano de Coahuila de Zaragoza), is one of the 32 states of Mexico. Coahuila borders the Mexican states of N ...

and

Nuevo León Nuevo León () is a state in the northeast region of Mexico. The state was named after the New Kingdom of León, an administrative territory from the Viceroyalty of New Spain, itself was named after the historic Spanish Kingdom of León. Wit ...

, and only abundant on the highest peak,

Cerro Potosí Cerro El Potosí is the highest mountain in the Sierra Madre Oriental mountain range of northeast Mexico. It is located in the state of Nuevo León, about 80 km (50 mi) south of Monterrey. Flora and fauna It is composed of lime ...

(3713 m). It occurs at very high altitudes, from 3000–3700 m, in cool, moist

subalpine climate The subarctic climate (also called subpolar climate, or boreal climate) is a climate with long, cold (often very cold) winters, and short, warm to cool summers. It is found on large landmasses, often away from the moderating effects of an ocean, ge ...

conditions.

Description

It is a medium-size

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from tree ...

, reaching 1.5–5 m tall and with a trunk diameter of up to 25 cm. The bark is grey-brown, thin and scaly at the base of the trunk. The

leaves A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

('needles') are in fascicles of five, slender, 3–5.5 cm long, and deep green to blue-green, with

stomata In botany, a stoma (from Greek ''στόμα'', "mouth", plural "stomata"), also called a stomate (plural "stomates"), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange. The pore is b ...

confined to a bright white band on the inner surfaces. The cones are globose, 3–4 cm long and broad when closed, green at first, ripening yellow-brown when 16–18 months old, with only a small number of thin, fragile scales, typically 6–14 fertile scales. The cones open to 4–6 cm broad when mature, holding the

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...

s on the scales after opening. The seeds are 9–12 mm long, with a thick shell, a white

endosperm The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven. It surrounds the embryo an ...

, and a vestigial 1–2 mm wing; they are dispersed by the

Clark's nutcracker Clark's nutcracker (''Nucifraga columbiana''), sometimes referred to as Clark's crow or woodpecker crow, is a passerine bird in the family Corvidae, native to the mountains of western North America. The nutcracker is an omnivore, but subsists mai ...

and Mexican jay, which pluck the seeds out of the open cones. The jays, which uses the seeds as a major food resource, store many of the seeds for later use, and some of these stored seeds are not used and are able to grow into new plants.

History

Because of its isolation on a handful of remote mountain summits, Potosí pinyon escaped discovery until 1959. It differs from most other pinyon species in needle number, with 5 per fascicle, rather than 1–4, and in its consistently shrubby stature. It is most closely related to Johann's pinyon and Orizaba pinyon, like them having the leaf stomata confined to the inner faces; it also differs from the latter in its smaller cones and seeds. Like these two, the white-glaucous inner surfaces of the needles make it a very attractive slow-growing shrub, suitable for small

garden A garden is a planned space, usually outdoors, set aside for the cultivation, display, and enjoyment of plants and other forms of nature. The single feature identifying even the wildest wild garden is ''control''. The garden can incorporate bot ...

s. Like other pinyons, the pine nut seeds are edible, but the inaccessibility of the plants prevents significant collection for food.

References

External links

Photos of shrubs and foliage (scroll half-way down)
{{Taxonbar, from=Q3506484 culminicola Endemic flora of Mexico Flora of Coahuila Flora of Nuevo León Trees of Northeastern Mexico Flora of the Sierra Madre Oriental Endangered biota of Mexico Endangered flora of North America