Platycladus

Platycladus orientalis
Platycladus orientalis Morton Arboretum acc. 168-53#3[1]
Conservation status
Near Threatened (IUCN 2.3)
Scientific classification
Kingdom:	Plantae
Division:	Pinophyta
Class:	Pinopsida
Order:	Pinales
Family:	Cupressaceae
Genus:	Platycladus
Species:	P. orientalis
Binomial name
Platycladus orientalis (L.) Franco[2]

Platycladus is a distinct genus of evergreen coniferous tree in the cypress family Cupressaceae, containing only one species, Platycladus orientalis, also known as Chinese Arborvitae or Biota. It is endemic to Northwestern China. It is also now naturalised as an introduced species elsewhere in Asia: eastward to Korea and Japan; southward to northern India; and westward to northern Iran;

Characteristics

Although generally accepted as only member of its genus, it has been suggested that the closely related species Microbiota decussata could be included in Platycladus, but this is not widely followed. Other fairly close relatives are the genera Juniperus and Cupressus, both of these genera being graft-compatible with Platycladus. In older texts, Platycladus was often included in Thuja, but it is only distantly related to that genus. Differences from Thuja include its distinct cones, wingless seeds, and its almost scentless foliage.

Growth

foliage and cones

It is a small, slow-growing tree, to 15-20 m tall and 0.5 m trunk diameter (exceptionally to 30 m tall and 2 m diameter in very old trees). The foliage forms in flat sprays with scale-like leaves 2-4 mm long. The cones are 15-25 mm long, green ripening brown in about 8 months from pollination, and have 6-12 thick scales arranged in opposite pairs. The seeds are 4-6 mm long, with no wing.

Etymology

The common name 'arborvitae' is from Latin, 'tree of life', and is based on its association with long life and vitality in Buddhist thought in China. This is probably based on the tree's unchanging evergreen nature in the cold dry climate of northwest China, and its longevity; some of the larger specimens planted around Buddhist temples in China are said to be in excess of 1,000 years old. It is called ce bai (側柏) in Chinese.

Uses

It is very widely used as an ornamental tree, both in its homeland, where it is associated with long life and vitality, and very widely elsewhere in temperate climates. The wood is used in Buddhist temples, both for construction work, and chipped, for incense burning.

See also

• Chinese herbology 50 fundamental herbs

References

1. ^ Cirrus Digital: Platycladus orientalis Morton Arboretum accession 168-53#3
2. ^ "Platycladus orientalis information from NPGS/GRIN". http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?310211. Retrieved 2008-02-19. 

General references

• Conifer Specialist Group (1998). Platycladus orientalis. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 6 May 2006.
• Gymnosperm Database - Platycladus orientalis
• Arboretum de Villardebelle - Platycladus cone photos