''Tsuga dumosa'', commonly called the Himalayan hemlock or in

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of v ...

, Yunnan tieshan (), is a species of conifer native to the eastern Himalayas. It occurs in parts of Nepal, India, Bhutan, Myanmar, Vietnam and Tibet. Within its native range the tree is used for construction as well as for furniture. In Europe and North America, it is occasionally encountered as an ornamental species and was first brought to the United Kingdom in 1838.

Description

''Tsuga dumosa'' is a tree growing high and exceptionally to . The

diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid for ...

at breast height is typically , but can be beyond . The crown on small trees is ovoid and their form is like that of pendulous bushes. Older trees tend to have multiple stems from one or two sinuous boles, especially in cultivation. The crown of mature trees is broad, irregular-pyramidal and open. The bark is a similar to that of an old

larch Larches are deciduous conifers in the genus ''Larix'', of the family Pinaceae (subfamily Laricoideae). Growing from tall, they are native to much of the cooler temperate northern hemisphere, on lowlands in the north and high on mountains furt ...

: somewhat pinkish to grey-brown and heavily ridged with broad, shallow, flaky fissures. The

branch A branch, sometimes called a ramus in botany, is a woody structural member connected to the central trunk of a tree (or sometimes a shrub). Large branches are known as boughs and small branches are known as twigs. The term ''twig'' usually ...

es are oblique or horizontal. The twigs are reddish brown or greyish yellow in their first year and are pubescent, i.e. covered with short hairs. Branches that are 2 to 3 years old are greyish brown or dark grey with leaf scars. The

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...

from the tree is a brownish yellow with a fine structure and straight veins. The

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

are spirally arranged, pointing forward on the branches and placed distantly from one another compared to other species in the genus ''

Tsuga ''Tsuga'' (, from Japanese (), the name of ''Tsuga sieboldii'') is a genus of conifers in the subfamily Abietoideae of Pinaceae, the pine family. The common name hemlock is derived from a perceived similarity in the smell of its crushed foliag ...

''. They are linear in shape, and long by wide. The ends are obtuse or rounded, and very occasionally emarginate. The upper surface of the leaves is green and shiny, while the undersides have 2 wide silvery stomatal bands. The upper half of the leaves usually have small dents on the margins, i.e. the margins are rarely entire. The

midrib This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary ...

is concave on the upper surface. The staminate

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanis ...

s are globose in shape, solitarily arranged and axillary. The

anther The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

s are a green-yellow in colour and they lack an air sac. The pistillate flowers are round-ovate in shape, also solitarily arranged, terminal and slightly down-curved. They have many spiral scales with 2

ovule In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the fem ...

s contained within each scale. The

seed A seed is an Plant embryogenesis, embryonic plant enclosed in a testa (botany), protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, includ ...

s are about long, ovate in shape, brown in colour and have thin wings in their upper parts. Flowering occurs from April to May and fruiting from October to November.

Range and habitat

''Tsuga dumosa'' is generally associated with the Himalayas. In India, it occurs from

Uttarakhand Uttarakhand ( , or ; , ), also known as Uttaranchal ( ; the official name until 2007), is a state in the northern part of India. It is often referred to as the "Devbhumi" (literally 'Land of the Gods') due to its religious significance and ...

in the west to

Arunachal Pradesh Arunachal Pradesh (, ) is a state in Northeastern India. It was formed from the erstwhile North-East Frontier Agency (NEFA) region, and became a state on 20 February 1987. It borders the states of Assam and Nagaland to the south. It shares int ...

in the east. The range continues southeast to northern Myanmar and Vietnam, and northeast to southeastern Tibet, northwestern

Yunnan Yunnan , () is a landlocked province in the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is Kunming. The province borders the ...

and southwestern

Sichuan Sichuan (; zh, c=, labels=no, ; zh, p=Sìchuān; alternatively romanized as Szechuan or Szechwan; formerly also referred to as "West China" or "Western China" by Protestant missions) is a province in Southwest China occupying most of the ...

. In Vietnam it is only found at altitudes above on Hoang Lien Son Mountain. In that country it is usually mixed with ''

Rhododendron ''Rhododendron'' (; from Ancient Greek ''rhódon'' "rose" and ''déndron'' "tree") is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are nat ...

spp.'' and ''

Abies pindrow ''Abies pindrow'', the pindrow fir or west Himalayan fir, is a fir native to the western Himalaya and adjacent mountains, from northeast Afghanistan east through northern Pakistan and India to central Nepal. Description It is a large evergre ...

'', though it can sometimes form a pure stand. It is adapted to areas with a cold climate and high rainfall and high humidity.

References

{{Taxonbar, from=Q476189 dumosa Trees of Myanmar Trees of China Flora of India (region) Flora of East Himalaya Flora of Assam (region) Trees of Nepal Trees of Vietnam Flora of Sichuan Flora of Tibet Flora of Yunnan