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piñón, single leaf pinyon, single-leaf pine, singleleaf pinyon pine

Chihuahua white pine, Mexican white pine, pino enano, Southwestern white pine

Habit Trees to 14m; trunk to 0.5m diam., strongly tapering, much branched; crown usually rounded, dense. Trees to 30m; trunk to 0.9m diam., slender, straight; crown conic, becoming rounded to irregular.
Bark

red-brown, irregularly furrowed or cross-checked, scaly.

gray, aging red-brown, furrowed, with narrow, irregular, scaly ridges.

Branches

spreading and ascending, persistent to near trunk base;

twigs stout, orange-brown, aging brown to gray, sometimes sparsely puberulent.

spreading-ascending;

twigs slender, pale red-brown, puberulous or glabrous, sometimes glaucous, aging gray or gray-brown, smooth.

Buds

ellipsoid, light red-brown, 0.5–0.7cm, resinous;

scale margins fringed.

ellipsoid, red-brown, ca. 1cm, resinous.

Leaves

1(–2) per fascicle, ascending, persisting 4–6(–10) years, 2–6cm × 1.3–2(–2.5)mm, curved, terete (though often 2-grooved), gray-green, all surfaces with stomatal lines, margins entire, apex subulate;

sheath 0.5–1cm, scales soon recurved, forming rosette, shed early.

5 per fascicle, spreading to ascending-upcurved, persisting 3–5 years, 4–9cm × 0.6–1mm, straight, slightly twisted, pliant, dark green to blue-green, abaxial surface without evident stomatal lines, adaxial surfaces conspicuously whitened by narrow stomatal lines, margins sharp, razorlike and entire to finely serrulate, apex narrowly acute to short-subulate;

sheath 1.5–2cm, shed early.

Pollen cones

ellipsoid, ca. 10mm, yellow.

cylindric, ca. 6–10mm, pale yellow-brown.

Seed(s)

cones maturing in 2 years, shedding seeds and falling soon thereafter, spreading, symmetric, ovoid before opening, broadly depressed-ovoid to nearly globose when open, 4–6(–8)cm, pale yellow-brown, nearly sessile;

apophyses thickened, slightly raised;

umbo subcentral, raised or depressed, nearly truncate, apiculate.

cones maturing in 2 years, shedding seeds and falling soon thereafter, pendent, symmetric, lance-cylindric before opening, broadly lance-cylindric when open, 15–25cm, creamy brown to light yellow-brown, stalks to 6cm;

apophyses somewhat thickened, strongly cross-keeled, tip reflexed;

umbo terminal, low.

2n

=24.

=24.

Pinus monophylla

Pinus strobiformis

Habitat Dry low-montane or foothill pinyon-juniper woodland Arid to moist summit elevations, montane forests
Elevation 1000–2300m (3300–7500ft) 1900–3000m (6200–9800ft)
Distribution
from FNA
AZ; CA; ID; NV; UT; Mexico in Baja California
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; NM; TX; n Mexico
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[BONAP county map]
Discussion

Pinus monophylla hybridizes with P. edulis and P. quadrifolia.

Singleleaf pinyon (Pinus monophylla) is the state tree of Nevada.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

In the northern part of the range, Pinus strobiformis overlaps P. flexilis and reportedly hybridizes with it. On average P. strobiformis has longer, more slender leaves and thinner, more spreading-tipped apophyses than are found in P. flexilis, and stomatal bands are not evident on the abaxial surface of its leaves.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 2. FNA vol. 2.
Parent taxa Pinaceae > Pinus Pinaceae > Pinus
Sibling taxa
P. albicaulis, P. aristata, P. attenuata, P. balfouriana, P. banksiana, P. cembroides, P. clausa, P. contorta, P. coulteri, P. echinata, P. edulis, P. elliottii, P. engelmannii, P. flexilis, P. glabra, P. jeffreyi, P. lambertiana, P. leiophylla, P. longaeva, P. monticola, P. muricata, P. palustris, P. ponderosa, P. pungens, P. quadrifolia, P. radiata, P. resinosa, P. rigida, P. sabiniana, P. serotina, P. strobiformis, P. strobus, P. sylvestris, P. taeda, P. torreyana, P. virginiana, P. washoensis
P. albicaulis, P. aristata, P. attenuata, P. balfouriana, P. banksiana, P. cembroides, P. clausa, P. contorta, P. coulteri, P. echinata, P. edulis, P. elliottii, P. engelmannii, P. flexilis, P. glabra, P. jeffreyi, P. lambertiana, P. leiophylla, P. longaeva, P. monophylla, P. monticola, P. muricata, P. palustris, P. ponderosa, P. pungens, P. quadrifolia, P. radiata, P. resinosa, P. rigida, P. sabiniana, P. serotina, P. strobus, P. sylvestris, P. taeda, P. torreyana, P. virginiana, P. washoensis
Synonyms Caryopitys monophylla, P. californiarum, P. cembroides var. monophylla P. ayacahuite var. brachyptera, P. ayacahuite var. reflexa, P. ayacahuite var. strobiformis, P. flexilis var. reflexa, P. reflexa
Name authority Torrey & Frémont: in Frémont, Rep. Exped. Rocky Mts. 2: 319, plate 4. (1845) Engelmann: in Wislizenus, Mem. Tour N. Mexico 102. (1848)
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