Pinus squamata

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Pinus squamata
Systematics
Order : Conifers (Coniferales)
Family : Pine family (Pinaceae)
Subfamily : Pinoideae
Genre : Pine ( Pinus )
Subgenus : Strobus
Type : Pinus squamata
Scientific name
Pinus squamata
XWLi

Pinus squamata is a plant from the genus of pine trees ( Pinus ) within the family of the Pinaceae (Pinaceae). The trunk bark dissolves in irregular scales. This endemic occurs only at one site in the northeastern part of the Chinese province of Yunnan and there are only about 36 specimens, of which about 20 are fully grown. This makes it probably the rarest species of pine and one of the rarest conifers of all. It is therefore classified as "Critically Endangered" inthe IUCN Red List .

description

Appearance

Pinus squamata grows as an evergreen tree that can reach heights of up to 20 meters. The trunk is upright and reaches a diameter of up to 60 centimeters at chest height , but no old trees are known. The trunk bark is smooth, hard and peels off in irregular, thin scales that expose light, yellowish spots that later turn from gray-green to various shades of brown and thus form a multicolored pattern on the trunk. The main branches grow in false whorls , spread out or ascending and form a conical to round, open crown. Needle twigs are thin, smooth, initially pale reddish brown and later gray-brown, densely yellow-brown or gray-brown hairy or hairless.

Buds and needles

The vegetative buds are resinous and egg-shaped with a length of up to 10 millimeters. The lower leaves are red-brown, arranged like roof tiles and triangular-lanceolate.

The needles grow in groups of four or five in a decrepit, basal needle sheath. They are light green, stiff or flexible, spreading, 9 to 17 centimeters long, with a broad triangular cross-section and a diameter of about 0.8 to 1.0 millimeters. The edge of the needle is finely sawn, the end pointed. There are stomata lines on all needle sides . A single bundle of wires and three to five large resin channels are formed near the surface.

Cones and seeds

The pollen cones grow spirally arranged in elongated groups on young shoots in the axils of broad lower leaves. They are oval-cylindrical and 10 to 15 millimeters long.

The seed cones grow individually, upright or horizontally on a 1.5 to 2.0 centimeter long stem. They are initially green and later variably brown, closed ovoid-conical, open with a length of 7 to, mostly 8 to 10 centimeters and a diameter of 5 to 6 centimeters wide-ovoid. They fall from the tree when they are ripe. The 100 to 120 seed scales are elongated-elliptical, woody and stiff with a length of about 2.7 centimeters and a width of about 1.8 centimeters. The apophysis is thickened, broadly rhombic in outline and keeled transversely. The triangular umbo lies dorsally, it is flat or more or less deepened and has no spine .

The black-striped seeds are 8 to 10 millimeters long and about 5 millimeters in diameter, oblong or obovate and slightly flattened. The seed wing is 15 millimeters long, articulated and also shows black stripes.

The pollination takes place in April and May, the seeds ripen in September and October, the then two-year old journal.

Distribution, locations and endangerment

This endemic occurs only at one site in Qiaojia County in the northeastern part of the Chinese province of Yunnan .

Pinus squamata is an extremely rare species that grows at altitudes nearly 2200 meters on a mountainside with open, human-disturbed woodland and grassland with bushes. They are found together with Pinus yunnanensis and various deciduous trees. The distribution area is assigned to winter hardiness zone 9 with mean annual minimum temperatures between −6.6 and −1.2 ° Celsius.

In the Red List of the IUCN in 2010 Pinus squamata due to the very limited distribution area and the very small population of only 36 copies, of which 18 are full-grown to 20 classified as "threatened with extinction" of (= "Critically Endangered"). Another count assumes a total of only 29 specimens, of which only 18 have cones. The distribution area lies on a partially deforested northwest slope and is surrounded by fire-prone grass and scrubland. An additional danger arises from crossing with Pinus yunnanensis . In the severe winter of 2008, three of the specimens died from heavy snowfall. However, the area is now a nature reserve and the trees are strictly protected. With the support of the local forest rangers and a farmer, several young trees were grown that will later be planted in the distribution area (status 2010).

Systematics and research history

Pinus squamata was only discovered in 1991 by Pangzhao JQ, examined by Xiang-Wang Li in 1991 and published by him in 1992 in Acta Botanica Yunnanica , Volume 14, Issue 3, pages 259-260, f. 1 first described . The type material was deposited by Xiang-Wang Li with the number 91250. The specific epithet squamata comes from Latin and means "scaly"; it refers to the scaly bark of older trees. A synonym of Pinus squamata X.W.Li is Pinus bungeana subsp. squamata (XWLi) Silba

The species Pinus squamata belongs with two other species to the sub-section Gerardianae from the section Quinquefoliae in the sub-genus Strobus within the genus Pinus . The scaly bark, the needle shape and the structure of the seed cones show the relationship to Pinus bungeana and Pinus gerardiana , the other two species of the Gerardianae subsection . It differs from these in the darker bark, the longer needles, which grow in groups of four or five in the needle sheaths, and the large, functional seed wings. These properties can otherwise be found in the types of the Strobus subsection .

use

Pinus squamata is not used economically. It may later be found in botanical gardens, initially only in China.

swell

literature

  • Li Xiang-Wang: A new series and a new species of Pinus from Yunnan. In: Acta Botanica Yunnanica Volume 14, Issue 3,1992, pp. 259-260.
  • Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 90-04-17718-3 , pp. 760-761 .
  • James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 478 .
  • Wu Zheng-yi, Peter H. Raven (Ed.): Flora of China . Volume 4: Cycadaceae through Fagaceae . Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 1999, ISBN 0-915279-70-3 , pp. 21 (English).

Individual evidence

  1. ↑ a b Pinus squamata in the IUCN Red List of Threatened Species 2019.1. Posted by: Y. Yang, T. Christian, 2010. Retrieved April 28, 2019.
  2. ↑ a b c d e f g h i Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 760
  3. ↑ a b c d e f g James E. Eckenwalder: Conifers of the World , p. 478
  4. ↑ a b Liguo Fu, Nan Li, Thomas S. Elias, Robert R. Mill: Pinus : Pinus squamata , p. 21 - online with the same text as the printed work , in Wu Zheng-yi, Peter H. Raven (ed.): Flora of China. Volume 4: Cycadaceae through Fagaceae. Science Press and Missouri Botanical Garden Press, Beijing and St. Louis 1999, ISBN 0-915279-70-3 .
  5. ↑ a b c d Christopher J. Earle: Pinus squamata. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed on July 26, 2013 .
  6. ↑ a b Pinus squamata at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed on April 28, 2019.
  7. ↑ Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 , p. 607 (reprint from 1996).
  8. ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 761

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