Larch

This article is about larch trees. Template:Alternateuses

Larches are conifers in the genus Larix, in the family Pinaceae. They are native to much of the cooler temperate northern hemisphere, on lowlands in the far north, and high on mountains further south. Larches are among the dominant plants in the immense boreal forests of Russia and Canada.

They are deciduous trees, growing from 15-50 m tall. The shoots are dimorphic, with growth divided into long shoots typically 10-50 cm long and bearing several buds, and short shoots only 1-2 mm long with only a single bud. The leaves are needle-like, 2-5 cm long, slender (under 1 mm wide). They are borne singly, spirally arranged on the long shoots, and in dense clusters of 20-50 needles on the short shoots. The needles turn yellow and fall in the late autumn, leaving the trees leafless through the winter.

Larch cones are erect, small, 1-9 cm long, green or purple, ripening brown 5-8 months after pollination; in about half the species the bract scales are long and visible, and in the others, short and hidden between the seed scales. Those native to northern regions have small cones (1-3 cm) with short bracts, with more southerly species tending to have longer cones (3-9 cm), often with exserted bracts, with the longest cones and bracts produced by the southernmost species, in the Himalaya.

Species and classification

There are 10-14 species; those marked '*' in the list below are not accepted as distinct species by all authorities. In the past, the cone bract length was often used to divide the larches into two sections (sect. Larix with short bracts, and sect. Multiserialis with long bracts), but genetic evidence does not support this division, pointing instead to a genetic divide between Old World and New World species, with the cone and bract size being merely adaptations to climatic conditions.

Old World

• Larix decidua (syn. L. europaea) European Larch. Mountains of central Europe.
• Larix gmelinii (syn. L. dahurica) Dahurian Larch. Plains of eastern Siberia.
• Larix griffithii (syn. L. griffithiana) Himalayan Larch. Mountains of eastern Himalaya
• Larix himalaica Langtang Larch *. Mountains of central Himalaya.
• Larix kaempferi (syn. L. leptolepis) Japanese Larch. Mountains of central Japan.
  Missing image
  Flowers_of_Japanese_larch_emerging.jpg

  Male (above) and female (below right) cones of Japanese Larch emerging in spring
• Larix kongboensis Tibetan Larch *. Mountains of southeast Tibet, northeast of L. grffithii.
• Larix mastersiana Masters' Larch. Mountains of western China.
• Larix potaninii Chinese Larch. Mountains of southwestern China (Sichuan, northern Yunnan).
• Larix principis-rupprechtii Prince Rupprecht's Larch *. Mountains of northern China (Shanxi, Hebei).
• Larix sibirica Siberian Larch. Plains of western Siberia.
• Larix speciosa Yunnan Larch *. Mountains of southwesternmost China (southwest Yunnan), northeast Myanmar.

New World

• Larix laricina Tamarack Larch or American Larch. Plains of northern North America.
• Larix lyallii Subalpine Larch. Mountains of northwest USA and southwest Canada, at very high altitude.
• Larix occidentalis Western Larch. Mountains of northwest USA and southwest Canada, at lower altitudes.

Most if not all of the species can be hybridised in cultivation; the best known hybrid is Larix x marschlinsii (a.k.a. L. x eurolepis, an illegitimate name), the Dunkeld Larch, which arose more or less simultanously in Switzerland and Scotland when L. decidua and L. kaempferi hybridised when planted together.

Uses

Larch is valued in forestry for its wood, which is tough, waterproof and durable, with top quality knot-free timber being in great demand for building yachts and other small boats. Larch has also been used in herbal medicine; see Bach flower remedies for details.

Larch is used as a food plant by the larvae of some Lepidoptera species including Autumnal Moth, Scalloped Hazel and The Engrailed.

External links

• Gymnosperm Database - Larix (http://www.botanik.uni-bonn.de/conifers/pi/la/index.htm)da:Lærk (Larix)

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