''Pinus johannis'', the Johann's pine, is a

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. ''World Flora Online'' accepts 134 species-rank taxa (119 species and 15 nothospecies) of pines as cu ...

in the

pinyon pine The pinyon or piñon pine group grows in southwestern North America, especially in New Mexico, Colorado, Arizona, and Utah, with the single-leaf pinyon pine just reaching into southern Idaho. The trees yield edible Pine nut, nuts, which are a sta ...

group, native to

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. The range extends from southeast

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

and southwest

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, south in

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

along the

Sierra Madre Occidental The Sierra Madre Occidental is a major mountain range system of the North American Cordillera, that runs northwest–southeast through northwestern and western Mexico, and along the Gulf of California. The Sierra Madre is part of the American C ...

and the

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 ...

to southern

Zacatecas Zacatecas, officially the Free and Sovereign State of Zacatecas, is one of the Political divisions of Mexico, 31 states of Mexico. It is divided into Municipalities of Zacatecas, 58 municipalities and its capital city is Zacatecas City, Zacatec ...

and

San Luis Potosí San Luis Potosí, officially the Free and Sovereign State of San Luis Potosí, is one of the 32 states which compose the Federal Entities of Mexico. It is divided in 59 municipalities and is named after its capital city, San Luis Potosí. It ...

. It occurs at moderate to high altitudes, from , in cool, dry climate conditions.

Description

''Pinus johannis'' is a small to medium-size

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

, often just a

shrub A shrub or 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 trees by their multiple ...

, reaching tall and with a trunk diameter of up to . The bark is grey-brown, thin and scaly at the base of the trunk. The

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

('needles') are in mixed fascicles of three and four, slender, long, and deep green to blue-green, with

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

confined to a bright white band on the inner surfaces. The

cones In geometry, a cone is a three-dimensional figure that tapers smoothly from a flat base (typically a circle) to a point not contained in the base, called the ''apex'' or '' vertex''. A cone is formed by a set of line segments, half-lines, ...

are globose, 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 6-12 fertile scales. The cones open to broad when mature, holding the

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s on the scales after opening. The seeds are 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#Pla ...

, and a vestigial wing; they are dispersed by the Mexican jay, which plucks the seeds out of the open cones. The jay, which uses the seeds as a major food resource, stores many of the seeds for later use; some of these stored seeds are not used and are able to grow into new trees. ''Pinus johannis'' is nearly

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

: nearly all individuals produce either male or female cones only, and trees do not appear to change their sex expression over time.

History

''Pinus johannis'' is a recently described

, discovered by Elbert L. Little in 1968 when comparing pinyons growing in Arizona with those of typical Mexican pinyon (''

Pinus cembroides ''Pinus cembroides'', also known as pinyon pine, Mexican pinyon, Mexican nut pine, and Mexican stone pine, is a pine in the pinyon pine group. It is a small pine growing to about with a trunk diameter of up to . It is native to western North Am ...

'') in Mexico; he described it as a

variety Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...

of Mexican pinyon, ''Pinus cembroides'' var. ''bicolor'', noting the very different stomatal placing on the leaves; it also differs in needle number, with 3–4 per fascicle, rather than 2–3; in the cones having thinner scales; and in having a denser, more rounded crown. Further research by the French botanist Marie-Françoise Robert-Passini, the American botanists Dana K. Bailey and Frank G. Hawksworth and others, has shown that it is better treated as a distinct

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

. Although often occurring together with Mexican pinyon, it is reproductively isolated from that by its

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma (botany), stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or bu ...

being a month to two months later in summer, rather than in spring, thereby preventing hybridisation. As Robert-Passini and Bailey & Hawksworth were working in different areas at about the same time, it was raised to species rank twice, first as ''Pinus johannis'' by Robert-Passini (naming it after her husband Jean) examining specimens in the Sierra Madre Oriental in Mexico, and then later as ''Pinus discolor'' by Bailey & Hawksworth examining specimens in the northern Sierra Madre Occidental in Arizona. There are slight differences between the plants in the two ranges; those in the eastern being more shrubby and with larger cones than those in the western range, and also differences in the

resin A resin is a solid or highly viscous liquid that can be converted into a polymer. Resins may be biological or synthetic in origin, but are typically harvested from plants. Resins are mixtures of organic compounds, predominantly terpenes. Commo ...

composition; they are though generally very similar and recognition of both as separate species from each other does not appear warranted. Some botanists also still include ''P. johannis'' in Mexican pinyon as a variety or even not distinguished at all, accounting for reports of "Mexican pinyon" in Arizona and New Mexico. This is despite the two frequently occurring together at the same sites with no hybridisation. ''Pinus johannis'' is most closely allied to Orizaba pinyon (''

Pinus orizabensis ''Pinus orizabensis'', the Orizaba pinyon, is a pine in the pinyon pine group, endemic to central Mexico. It is considered also as a sub-species of ''Pinus cembroides'' which is classified as ''Pinus cembroides'' subsp. ''orizabensis'' D.K.Baile ...

'') and Potosi pinyon (''

Pinus culminicola ''Pinus culminicola'', commonly known as Potosí pinyon or Potosí Piñón, is a pine in the pinyon pine group, native and endemic to northeast Mexico. The range is highly localised, confined to a small area of high summits in the northern Sier ...

''), with which it shares the leaf structure with the stomata confined to the inner faces; it differs from the former in the smaller cones and seeds, and from the latter in fewer needles per fascicle (3–4 vs 5).

Uses

The edible

pine nut Pine nuts, also called piñón (), pinoli (), or pignoli, are the edible seeds of pines (family Pinaceae, genus ''Pinus''). According to the Food and Agriculture Organization, only 29 species provide edible nuts, while 20 are traded locall ...

seeds are collected in Mexico to a small extent. The white-glaucous inner surfaces of the needles make it a very attractive small tree, suitable for

park A park is an area of natural, semi-natural or planted space set aside for human enjoyment and recreation or for the protection of wildlife or natural habitats. Urban parks are urban green space, green spaces set aside for recreation inside t ...

s and large

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 ...

References

External links

Pinetum.org – Photos of ''Pinus johannis'' tree and foliage (scroll half-way down)

{{Taxonbar, from=Q3506525 johannis Trees of Northern America Flora of the Southwestern United States Flora of Northwestern Mexico Flora of Northeastern Mexico Flora of Sonora Flora of Zacatecas Flora of San Luis Potosí Flora of Arizona Flora of New Mexico Flora of the Sierra Madre Occidental Flora of the Sierra Madre Oriental Edible nuts and seeds Garden plants of North America Drought-tolerant trees Dioecious plants Plants described in 1978 Flora without expected TNC conservation status