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Picea retroflexa

Picea retroflexa - Green dragon spruce, Tapao shan spruce
  • Picea retroflexa - Green dragon spruce, Tapao shan spruce  - Click to enlarge
  • Picea retroflexa branches - Click to enlarge
  • Picea retroflexa leaves - Click to enlarge

€30.00

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Product Information
Specification

 

Scientific name: Picea retroflexa  M.T.Masters  1906

Synonyms: Picea asperata var. retroflexa (Mast.) W.C.Cheng, Picea aurantiaca var. retroflexa (Mast.) C.T.Kuan & L.J.Zhou, Picea gemmata Rehder & E.H.Wilson

Common names: Green dragon spruce, Tapao shan spruce (English), Yun shan (Chinese)

 

Description

Trees to 40-45 m tall, d.b.h. to 1-1.5 m, trunk monopodial, straight. Bark on trunk rough and scaly, breaking into small, flaking plates, grey or brownish grey; inner bark yellowish. Branches of first order short, numerous, spreading horizontally, branches of second order short, rigid, numerous, spreading laterally. Crown narrowly conical or columnar, especially in trees at high altitude. Branchlets short, firm, thick, light brown or orange-brown, prominently ridged and deeply grooved, glabrous or often ferruginous pubescent; pulvini strongly developed, 1-2 × 1-1.5 mm, on strong shoots almost erect. Vegetative buds broadly conical, closely surrounded by curved leaves, 5-10 × 5-10 mm, resinous, often pubescent at base, bud scales triangular, keeled, appressed, orange-brown or with purplish apex, persisting several years, leaving broad collars of perular scales at shoot bases. Leaves spreading radially, curved forward, (1-)1.2-1.8(-2.5) cm long, (1.2-)1.5-2 mm wide, linear, curved, quadrangular or transversely rhombic in cross-section, with prominent ribs, apex pungent, amphistomatic, on upper surface 2 bands of 2-3 lines, on lower surface 2 bands of 4-6 lines of stomata. Leaf colour light green or glaucous green. Pollen cones axillary, 2 3-5 cm long, reddish, ripening to reddish yellow. Seed cones terminal, erect at first, then pendulous, sessile, oval-oblong to cylindric-conical, apex obtuse, 8-13 cm long, 2.5-4 cm wide with opened scales, immature cones purplish red, maturing to purplish or reddish brown, ripening to lustrous brown. Seed scales obovate-oblong or slightly obtrullate, those near base suborbicular, spreading wide when ripe, 1.5-2 × 1.2-1.5 cm at mid-cone, abaxial surface striated, shining, more or less convex, glabrous; upper margin rounded or obtuse, slightly erose-denticulate, incurved, straight or slightly reflexed when opened base cuneate. Bracts ligulate-lanceolate, 5-6 mm long, entirely included. Seeds ovoid-oblong, 3-4 mm long, dark brown or red-brown, seed wings obovate-oblong, 10-15 × 5-7 mm, pale brown or yellowish brown.

The species epithet (Latin retroflexus = 'bent back, reflexed') refers to the pulvini on the shoots, which Masters described as being "patenti-reflexi".

Endemic to China where it occurs in West Sichuan, Kangding, Jiuzhaigou (Zheduo Shan), Qinghai, and Ban Ma Xian; 3,000-4,000(-4,700) m.

 

Conservation Status

Red List Category & Criteria: Endangered

The available evidence supports a considerable past decline (50-70%) in Picea retroflexa's population although the situation is currently stable (three generations is 150 years). The species meets the criteria for listing as Endangered under criterion A2 based on the available evidence.

Picea retroflexa is a typical subalpine species, which occurs between 3,000 m and 4,000 m a.s.l. (to 4,700 m east of Dawu), mainly on north-facing slopes on acidic soils. The climate is continental alpine with low annual precipitation. At the highest elevations it grows either pure or mixed with Abies squamata, but at lower elevations Picea likiangensis var. rubescens, Picea aurantiaca, Abies chensiensis and Tsuga chinensis may occur with it. Betula albosinensis is the only common broad-leaved tree species in these forests.

Intensive unsustainable logging of montane and subalpine forests during the period from 1950 to 1990, coupled with the limited range of this taxon has led to a significant recent decline that is estimated to be more than 50%. An ongoing decline is suspected due to fires and grazing preventing natural regeneration and hampering afforestation efforts. The subpopulation near Jiuzhaigou has an estimated 450 trees; sizes of other subpopulations are unknown.

Although no uses are specifically reported of this species, its timber has been exploited together with that of other species in the area and put to the same uses. This spruce was introduced to Europe and the USA by Ernest Wilson and is still present in several arboreta, often identified as Picea asperata. According to Rushforth (1987), trees in cultivation (in the UK) are "noticeably greener than Dragon spruce" (Picea asperata), which could indicate that Wilson introduced seed from a green-leaved form of this species. As Wilson himself noted (on specimen), glaucous forms also occur in its native habitat. This 'mixture' of green and glaucous forms is common among conifers in all families and has given rise to both valuable horticultural varieties and much taxonomic confusion.

The Government of China has recently imposed a ban on logging in western China. One subpopulation is within Jiuzhaigou Valley Nature Reserve.

 

Cultivars:

Picea retroflexa ‘Blydenstein’  

 

References

  • Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.
  • Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.
  • IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland

Copyright © Aljos Farjon, James E. Eckenwalder, IUCN, Conifers Garden. All rights reserved.

Product CodePICVU78K87
Weight1.5 kg
Height20 - 25 cm
PropagationGraft

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