Syn.: Juniperus monosperma var. gracilis Martínez 1946. Type location Hacienda de Angostura, San Luis Potosí, Mexico (Farjon 2005).
DescriptionJuniperus angosturana is a small evergreen, dioecious tree or shrub, 3 - 8' (1 - 2.5 m )tall and up to 20" (50 cm) dbh, but often forking low. Bark smooth on branches, soon exfoliating in small flakes, then fissured or tesselated, light brown weathering to grey. Branches thick, spreading, tortuous, with drooping foliage, forming an irregularly domed crown. Foliage lax, ultimate branchlets 4-20 × 1-1.3 mm, leaves retained on 4-5 ultimate orders of branching. Leaves decussate or in alternating whorls of 3, imbricate, appressed, oblong-rhombic, 1-1.5 × 0.7 mm, upper margins minutely hyaline-serrulate, rarely glandular. Seed cones numerous, terminal on very short lateral branches, green turning purple-Blue, drying brown, 4-6 × 3-5 mm, maturing in one year. Seeds 1(-2), ovoid to subglobose, 3-5 × 2.5-4 mm, shallowly grooved, apex acute, light brown with a tan basal hilum (Farjon 2005).
Distribution and EcologyMexico: the Sierra Madre Oriental, in the states of Coahuila, Hidalgo, Nuevo León, San Luis Potosí, and Tamaulipas. Grows at 1100-2140 m elevation in open shrubland or piñon-juniper woodland, commonly with Pinus cembroides, Juniperus flaccida and sclerophyllous shrubs, on rocky slopes and along intermittent streams. Also recorded in open Pinus montezumae forest (Farjon 2005).
(From The Gymnosperm Database)