Pinus johannis, first described in 1978 by Marie-Françoise Robert, is commonly known as Johannis pine; as well as dwarf piñon; piñon, piñonero in the Spanish language. The species name honors Johann Passini, Marie Robert's fiance, whom she later married; she published subsequent papers first as M.-F. Robert-Passini and then as M.-F. Passini.
Pinus johannis is a recently described pinyon pine, discovered by Elbert L. Little in 1968 when comparing pinyons growing in Arizona with those of typical Mexican pinyon (Pinus cembroides) in Mexico; he described it as a variety 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. It was later determined to be the only known dioecious pine, strengthening to claim for distinct species status.
Ethnobotany. The branches of this small piñon are occasionally used for firewood and the seeds are collected for food. With its very attractive Blue-green foliage, it is potentially a valuable slow-growing ornamental species for small gardens in arid areas, but it is scarcely in cultivation yet.
Description. Johannis pine is a shrubby, evergreen conifers species of tree that grows to mature heights of 6 to 10 feet (2 - 3 m), most-commonly multi-stemmed, rarely with a single trunk. Crown is low, dense and rounded, spreading, with branches extending outward as much as 10 - 12 feet (3 - 4 m).
Bark in young trees is smooth and gray; in older trees rough and scaly, but not deeply furrowed or ridged.
Twigs are colored dark gray, rough textured, with somewhat decurrent bases of the leaf bracts.
Leaves (needles) are borne in bundle of 3 (sometimes 2 or 4) per fascicle. They grow 1.2 to 2 inches (3 - 5 cm) long, 0.036 to 0.048 (0.9 - 1.2 mm) thick. They're flexible with entire margins and lines of stomata present only on the ventral surfaces, with a distinctive variegated appearance because the dorsal surface is dark green and the ventral surfaces glaucous white. The 2 resin canals are external, dorsal; including a single vascular bundle single.
Fascicle sheaths are orange-brown, 0.12 inch (3 mm long), fading gray, and curled backward into a rosette; later occasionally deciduous.
Seed cones, in their first year brown are brown in color, measuring 0.36 to 0.44 inch (9 - 11 mm) long and 0.2 to 0.28 inch (5 - 7 mm) wide, borne singly or in pairs on short slender peduncles. At maturity they are chestnut brown, resinous, oblong shaped, measuring 1.2 to 1.6 inches (3 - 4 cm) long by 0.6 to 1.2 inches (2 - 3 cm) wide when closed, 1.6 to 2.2 inches (4 - 5.5 cm) wide when open, opening at maturity and soon deciduous. The peduncle is 3-4 mm long, falling with the cone.
Cone scales are thin and stiff, the apophyses irregularly rhomboid, small, thin, flat or slightly raised, 0.4 to 0.6 inch (10 - 15 mm) wide, with a weak transverse ridge. Umbo is dorsal, depressed, with a minute soon deciduous prickle. Only the central 8 to 15 scales are seed-bearing, those at the base and apex of the cone generally very small and sterile.
Seeds are dark orange-brown colored with a rudimentary 0.02 to 0.04 inch (0.5 - 1 mm) wing that remains in the cone after seed release. Seed body measures circa 0.44 to 0.56 inch (11 - 14 mm) long by 0.4 inch (10 mm) wide, with a thick, hard shell, 0.02 to 0.04 inch (0.5 - 1.0 mm) thick.
places where stands of Pinus johannis have been located.
Distribution. This species is native to Mexico — scattered in the higher ranges of western Coahuila, Nuevo León and Zacatecas at elevations of 5,600 and 9,200 feet (1,700 - 2,800 m) above sea level. The type locality is only in a very limited area near the towns of Concepción del Oro and Mazapil, state of Zacatecas. More recently a number of small populations have been reported in western Coahuila and in the area between the towns of Miquihuana and Aramberri, Nuevo León. Jessy Perry describes the Concepción del Oro stand as occurring at 8.900 feet (2,700 m) on a steep slope of practically bare limestone, in the company of P. cembroides. The area has 12 to 16 inches (300 - 400 mm) annual precipitation and average annual temperature of 60°F (16°C). Frosts are common during December and January.
Hardy to UDSA Zone 8 — cold hardiness limit between 10° and 20°F (-12.1° and -6.7°C).
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