''Picea koyamae'' (Koyama's spruce;

Japanese Japanese may refer to: * Something from or related to Japan, an island country in East Asia * Japanese language, spoken mainly in Japan * Japanese people, the ethnic group that identifies with Japan through ancestry or culture ** Japanese diaspor ...

: ヤツガタケトウヒ or やつがたけとうひ ''yatsugatake-touhi'') is a rare

spruce A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (taiga) regions of the Northern hemisphere. ''Picea'' ...

, endemic to the

Akaishi Mountains The are a mountain range in central Honshū, Japan, bordering Nagano Prefecture, Nagano, Yamanashi Prefecture, Yamanashi and Shizuoka Prefecture, Shizuoka prefectures. They are also called the , as they join with the Hida Mountains ("Northern Al ...

and

Yatsugatake Mountains The are a volcanic mountain range on the border between Nagano Prefecture and Yamanashi Prefecture on the island of Honshū in Japan. Description The mountain range consists of two volcanic groups, Northern Yatsugatake Volcanic Group and Southe ...

in central

Honshu , historically known as , is the largest of the four main islands of Japan. It lies between the Pacific Ocean (east) and the Sea of Japan (west). It is the list of islands by area, seventh-largest island in the world, and the list of islands by ...

, Japan. It is an

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

tree growing to tall, with a trunk diameter of up to a metre. It grows in small isolated stands in a limited area and the total area of occupation is less than . Trees that are lost to typhoons are normally replaced with other faster-growing species and the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

has assessed the tree as being "

critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

". Some trees are in cultivation for their ornamentality.

Description

It is a

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system comparable with gynomonoecy, andromonoecy and trimonoecy, and contras ...

tree growing to 25 m tall, with a trunk diameter of up to 1 m. The shoots are orange-brown, with scattered

pubescence Puberty is the process of physical changes through which a child's Human body, body matures into an adult body capable of sexual reproduction. It is initiated by hormone, hormonal signals from the Human brain, brain to the gonads: the ovary ...

. The

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

are needle-like, 8–16 mm long, rhombic in cross-section, dark bluish-green with conspicuous

stoma In botany, a stoma (: stomata, from Greek language, Greek ''στόμα'', "mouth"), also called a stomate (: stomates), is a pore found in the Epidermis (botany), epidermis of leaves, stems, and other organs, that controls the rate of gas exc ...

tal lines. The

cones In geometry, a cone is a three-dimensional figure that tapers smoothly from a flat base (typically a circle) to a point not contained in the base, called the ''apex'' or '' vertex''. A cone is formed by a set of line segments, half-lines, ...

are cylindric-conic, 4–9 cm long and 2 cm broad, maturing pale brown 5–7 months after

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma (botany), stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or bu ...

, and have stiff, smoothly rounded scales 6–18 mm long and 6–12 mm wide. Pollination takes place in late spring.Gymnosperm Database
''Picea koyamae''
/ref>

Distribution

Koyama's spruce is native to the

and

, or Nagano and Yamanashi Prefectures in central

Honshū , historically known as , is the largest of the four main islands of Japan. It lies between the Pacific Ocean (east) and the Sea of Japan (west). It is the seventh-largest island in the world, and the second-most populous after the Indonesian ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

, where it grows at 1500–2000 m altitude.Farjon, A. (1990). ''Pinaceae. Drawings and Descriptions of the Genera''. Koeltz Scientific Books . It is found growing in groups of 10–20, with a total population of only about 250 mature trees. The main cause of decline is the loss of natural regeneration after

typhoon A typhoon is a tropical cyclone that develops between 180° and 100°E in the Northern Hemisphere and which produces sustained hurricane-force winds of at least . This region is referred to as the Northwestern Pacific Basin, accounting for a ...

s, with windblown trees being replaced by the planting of other faster-growing commercially valuable species. Other threats include wildfires, landslides and changes in temperature and precipitation associated with climate change. There is little genetic exchange between different fragmentary locations where it grows, and the total area of occupation by this tree is less than . The tree is named after the Japanese

botanist Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

Mitsua Koyama. The name was first published as "koyamai", but this is an orthographical error to be corrected under the provisions of

ICBN The ''International Code of Nomenclature for algae, fungi, and plants'' (ICN or ICNafp) is the set of rules and recommendations dealing with the formal botanical names that are given to plants, fungi and a few other groups of organisms, all tho ...

Article 60.Farjon, A. (1998). ''World Checklist and Bibliography of Conifers''. Royal Botanic Gardens, Kew . It is occasionally planted as an

ornamental tree Ornamental plants or ''garden plants'' are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars th ...

. The wood is similar to that of other spruces, but the species is too rare to be of economic value. Image:Picea koyamai.jpg, Recently dead specimen in the

Arboretum de Chèvreloup The Arboretum de Versailles-Chèvreloup (; 200 hectares) is a major arboretum located just north of the Palace of Versailles at 30, route de Versailles, Rocquencourt, Yvelines, Île-de-France, France. It forms part of the Muséum national d'hist ...

, France File:Picea koyamae shoot.JPG, Young shoot, Arboretum in Rogów, Poland File:Picea koyamae - immatures cones.jpg, Immature cones

References

{{Taxonbar, from=Q391374 koyamae Endemic flora of Japan Trees of Japan Critically endangered flora of Asia