 | Pinus juarezensis Lanner 1974Common NamesSierra Juárez pinyon, nut pine, piñon (1).Taxonomic notesSubsection Cembroides. Lanner (2) regards the P. quadrifolia populations described for the Sierra Juárez as P. juarezensis-P. monophylla hybrids and segregates P. juarezensis as a 5-needle piñon endemic to the Sierra Juárez of Baja California Norte and extreme S CA, reducing P. quadrifolia to hybrid status as P. × quadrifolia Parl. Farjon and Styles (3) regard P. juarezensis as a synonym for P. quadrifolia, discounting the idea that because P. quadrifolia displays characters intermediate between P. monophylla and P. juarezensis it must then be a hybrid. This is a valid point, but does not address the fact that Lanner does describe some populations of P. juarezensis -- such as that atop the Laguna Mountains in California -- that do not display hybrid characters and that do seem to be distinct from P. quadrifolia in certain ways, such as in consistently having 5 needles per fascicle. Resolution of this problem probably awaits genetic studies. Meanwhile, Perry (1) and others (including this treatment) regard P. juarezensis and P. quadrifolia as distinct, valid species.Description"A small pine up to 15 m tall. In mature trees the crown is irregularly rounded; in young trees it is thicker and narrowly pyramidal. [Bark is] in old trees, thick, scaly, divided by longitudinal and horizontal furrows; in young trees thin and smooth. [Branchlets] light gray, rough, pubescent; bases of the leaf bracts are not decurrent. [Leaves] in fascicles of 5, rarely 4, slightly curved, 1.5-4.0 cm long, 0.5-1.5 mm thick; margins entire, stomata primarily on the ventral surfaces with an occasional row on the dorsal surface; resin canals 2, rarely 1 or 3, dorsal; fibrovascular bundle single; the leaves bright green on the dorsal surface and silver-colored (lines of stomata) on the ventral surfaces; connate (united) during the first year. Sheaths of the leaves 5-9 mm long, curled into persistent rosettes, later deciduous. [Conelets] borne singly and in pairs on slender, short peduncles; globose with thick, transversely keeled scales. [Cones] subglobose; symmetrical; 3.5-5.0 cm long, 4.5-7.0 cm wide when open; yellow to ochre colored; dehiscent; deciduous when mature, the peduncle very small and falling with the cone. [Cone scales] few; the apophysis rhomboidal, transversely keeled; the umbo dorsal, flat to depressed, bearing a minute early deciduous prickle. Only the central scales are seed-bearing. [Seeds] brown; wingless; 14-17 mm long, 6-8 mm wide; the seed coat very thin, 0.2-0.3 mm thick; the endosperm white" (1).RangeUS: S California and Mexico: Baja California Norte. "Its principal range lies in the Sierra de Juárez and Sierra de San Pedro Mártir in Baja California Norte. [Habitat is] semi-arid to arid foothills and mesas at altitudes ranging from 1,100 to 2,000 m. Rainfall at the lower elevations generally does not exceed 500 mm annually and temperatures may drop to freezing during the winter months. At the higher altitudes (1,600-2,000 m) frosts often occur during the winter and annual rainfall may reach 600 mm with about 30% occurring in the form of snow and sleet. Associated piñon pines are P. monophylla and P. quadrifolia" (1).Big TreeOldestDendrochronologyEthnobotanyThe seeds are "sold on the market as pine nuts along with the seeds of P. edulis and P. monophylla ... Like most of the nut pines, the trunk is short and small in diameter and thus hardly useful for sawn lumber. However, it is used locally for posts and firewood" (1).Observations"This species can be found in southern California, San Diego County, growing in the Laguna Mountains on Mt. Laguna, within the Cleveland National Forest at 1,800-2,000 m. South of the border in Baja California Norte, take MEX Highway 2 east from Tijuana to Tecate (also on the border). At Tecate take MEX Highway 3 south into the Sierra de Juárez and look for the trees along the highway at altitudes of 1,200-1,500 m. To collect at the type location, follow MEX Highway 2 east from Tecate toward the village of Rumorosa. About 2 km before reaching Rumorosa, look for this species near the road on the right" (1).Remarks"The rather large, thin-shelled seeds are gathered for food by birds and rodents" (1).Citations(1) Perry 1991.(2) Lanner 1974a, 1974b, 1981. (3) Farjon & Styles 1997. |
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