Juniperus monosperma

Juniperus monosperma
Juniperus monosperma
Conservation status
Scientific classification
Kingdom: Plantae
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Cupressaceae
Genus: Juniperus
Species: J. monosperma
Binomial name
Juniperus monosperma
(Engelm.) Sarg.

Juniperus monosperma (One-seed Juniper) is a species of juniper native to western North America, in the United States in Arizona, New Mexico, southern Colorado, western Oklahoma (Panhandle), and western Texas, and in Mexico in the extreme north of Chihuahua. It grows at 970–2300 m altitude.[2][3]

It is a evergreen coniferous shrub or small tree growing to 2–7 m (rarely to 12 m) tall, usually multistemmed, and with a dense, rounded crown. The bark is gray-brown, exfoliating in thin longitudinal strips, exposing bright orange brown underneath. The ultimate shoots are 1.2–1.9 mm thick. The leaves are scale-like, 1–2 mm long and 0.6–1.5 mm broad on small shoots, up to 10 mm long on vigorous shoots; they are arranged in alternating whorls of three or opposite pairs. The juvenile leaves, produced on young seedlings only, are needle-like. The cones are berry-like, with soft resinous flesh, subglobose to ovoid, 5-7 mm long, dark blue with a pale blue-white waxy bloom, and contain a single seed (rarely two or three); they are mature in about 6–8 months from pollination. The male cones are 2-4 mm long, and shed their pollen in late winter. It is usually dioecious, with male and female cones on separate plants, but occasional monoecious plants can be found.[2][3] Its roots have been found to extend to as far as 61m below the surface, making it the plant with the second deepest roots, after Boscia albitrunca.[4]

Frequently, cones can be found with the seed apex exposed; these were formerly sometimes considered a separate species "Juniperus gymnocarpa", but this is now known to be due to insect damage to the developing cones (and can affect many different species of juniper); the seeds from such cones are sterile.[3]

It is very rare or even extinct in Mexico, with only a single herbarium collection from 1880 verified;[2] more recent searches have failed to find the species there.[3] A closely related species Juniperus angosturana was however formerly considered a variety, as J. monosperma var. gracilis Martínez; it differs from J. monosperma in its slenderer shoots 1.0–1.3 mm diameter.[2][3]

Unlike many other junipers, the wood is not durable, so is not used to any extent.[3]

Other vernacular names occasionally used include Single-seed Juniper and Cherrystone Juniper.

References

  1. ^ Conifer Specialist Group (1998). Juniperus monosperma
  2. ^ a b c d Farjon, A. (2005). Monograph of Cupressaceae and Sciadopitys. Royal Botanic Gardens, Kew. ISBN 1-84246-068-4
  3. ^ a b c d e f Adams, R. P. (2004). Junipers of the World. Trafford. ISBN 1-4120-4250-X
  4. ^ Stonea, E. L.; P. J. Kaliszb (1 December 1991). "On the maximum extent of tree roots". Forest Ecology and Management 46 (1-2): 59–102. doi:10.1016/0378-1127(91)90245-Q. 

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