Juniperus monticola

Juniperus monticola is a species of conifer in the Cupressaceae family. It is found only in Mexico.

Description

Dioecious evergreen shrubs or trees to 10 m tall. Foliage includes decurrent and scale types. Female cones (berries) are globose, 5-9(-10) mm diameter, Blue-black, glaucous, with a soft, fleshy pulp, usually on curved peduncles. Seeds (2-)3-7(-9) per cone, angular, grooved. Pollen shed in the fall. Other characters variable, as described below (Adams 2004).

Forma monticola is a tree or spreading shrub with tortuous branches, if a tree, then to 10 m with crown flattened to broadly conic. The bark is 5-10 mm thick, gray to gray-brown, exfoliating in fibrous, longitudinal strips. The terminal whip branches are spreading and tortuous to ascending, the tips occasionally curved, with red-brown to gray-brown bark. Scale leaves are usually opposite, gray-green to green, often thick, 1.0-2.0 mm long, rounded or obtuse with appressed tips, appearing as a string of beads on the ultimate twig. Their margins are finely denticulate, and there is sometimes an obvious resin gland on the surface of the leaf (Adams 2004).

Forma compacta is a prostrate shrub less than 1 m tall with twisted, procumbent branches. The bark is cinnamon brown, exfoliating in thin strips (Adams 2004).

Forma orizabensis is a shrub up to 1.5 m tall with twisted, spreading branches. Trunk bark is light brown, exfoliating in thin strips or plates.

Distribution and Ecology

Mexico. The formae have disjunct distributions, the type in subalpine to alpine settings, the others confined to the alpine zone, as follows:

Forma monticola: Widespread in rocky subalpine (above treeline on Nevado de Colima, Jalisco) oak-juniper, Pinus or Abies forests, as an understory shrub or small tree, at 2,400 to 4,300 m elevation. It is widespread and not of commercial significance, and thus is not threatened (Adams 2004).

Forma compacta: Native in Coahuila (Sierra Mojada), Distrito Federal (Cerro Pelado and Ajusco), Jalisco (Nevado de Colima), México (Popocatepetl, Iztaccihuatl, Tlaloc and Nevado de Toluca), Nuevo Leon (Cerro Potosí), Tlaxcala (Malinche), and Veracruz (Cofre de Perote). It is found at 3000-4300(-4500) m elevation at the alpine timberline (with Pinus hartwegii) above in Calamagrostis and Festuca mountain grasslands, often on rocky sites. The form has no commercial significance, and thus is not threatened (Adams 2004).

Forma orizabensis: Native in Veracruz (Pico de Orizaba, Sierra Nevada, and Cofre de Perote), Tamaulipas (Peña Nevada), where it grows at and above the alpine timberline on rocky sites at 3700-4500 m elevation; and also in San Luis Potosi (Mineral Catoree), where it occurs at 2850 m elevation in oak forest. Although it has a very limited distribution, it occurs in relatively undisturbed alpine sites and is not threatened (Adams 2004).

Hardy to Zone 7 (cold hardiness limit between -17.7°C and -12.2°C) (Bannister and Neuner 2001); the variety not specified.

The Gymnosperm Database