Gymnosperms (Seed Producing Plants: Conifers, Cycads, Ginkgo) • Earth.com

Creeping juniper

(Juniperus horizontalis)

galery
en

Description

Juniperus horizontalis, the creeping juniper or creeping cedar, is a low-growing shrubby juniper native to northern North America, throughout most of Canada from Yukon east to Newfoundland, and in some of the northern United States. Living up to both its scientific and common names, the species reaches only 10–30 centimetres (3+7⁄8–11+3⁄4 in) tall but often spreading several metres wide. The shoots are slender, 0.7–1.2 millimetres (1⁄32–1⁄16 in) diameter. The leaves are arranged in opposite decussate pairs, or occasionally in whorls of three; the adult leaf blades are scale-like, 1–2 mm long (to 8 mm on lead shoots) and 1–1.5 mm (1⁄32–1⁄16 in) broad, and derive from an adnate petiole. The juvenile leaves (on young seedlings only) are needle-like, 5–10 mm (3⁄16–3⁄8 in) long. The cones are berry-like, globose to bilobed, 5–7 mm (3⁄16–9⁄32 in) in diameter, dark blue with a pale blue-white waxy bloom, and contain two seeds (rarely one or three); they usually have a curved stem and are mature in about 18 months. The male cones are 2–4 mm (3⁄32–5⁄32 in) long, and shed their pollen in early spring. It is dioecious, producing cones of only one sex on each plant. It is closely related to Juniperus virginiana, and often hybridizes with it where their ranges meet in southern Canada. Hybrids with Juniperus scopulorum also occur. The species is native to northern North America, throughout most of Canada from Yukon east to Newfoundland, and in the United States in Alaska, and continentally from Montana east to Maine, reaching its furthest south in Wyoming and northern Illinois. Amongst the sites it occupies are rocky areas of the east slopes of the Rocky Mountains. Junipers are coniferous trees and shrubs in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere, from the Arctic, south to tropical Africa, throughout parts of western, central and southern Asia, east to eastern Tibet in the Old World, and in the mountains of Central America. The highest-known juniper forest occurs at an altitude of 4,900 metres (16,100 ft) in southeastern Tibet and the northern Himalayas, creating one of the highest tree lines on earth. Junipers vary in size and shape from tall trees, 20–40 metres (66–131 ft) tall, to columnar or low-spreading shrubs with long, trailing branches.

Taxonomic tree:

Domain:
Kingdom: Plantae
Phylum: Coniferophyta
Class: Pinopsida
Order:Pinales
Family:Cupressaceae
Genus:Juniperus
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