''Pinus pumila'' × ''P. sibirica'' is a putative hybrid of Japanese stone pine (''P. pumila'') and

Siberian pine ''Pinus sibirica'', or Siberian pine, in the family Pinaceae is a species of pine tree that occurs in Siberia from 58°E in the Ural Mountains east to 126°E in the Stanovoy Range in southern Sakha Republic, and from Igarka at 68°N in the l ...

(''P. sibirica''). It has not yet been officially described.

Description

Pinus pumila x pinus sibirica cross section

''Pinus pumila'' × ''P. sibirica'' is a small tree about tall with a broad open

crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, parti ...

, and dark brown

bark Bark may refer to: Common meanings * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Arts and entertainment * ''Bark'' (Jefferson Airplane album), ...

. The trunk is not vertical, it is often curved. Maximum height (from 1.5 to 3 m depending on light and

soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...

conditions) is reached at 100–150 years, and then height remains more or less constant. Once the tree reaches a height of 4–5 m (rarely 6–7 m and higher) damage to the branches becomes inevitable. The broken branches can take root, the ability to produce specialized roots from latent buds inherited from ''P. pumila''. These traits vary among sites where the hybrids are found. The pine cones of the tree resemble the cones of the Siberian pine (''P. sibirica''). The cones are larger and thicker and not as much elongated as Japanese stone pine (''P. pumila'') cones. On average the cones are 4 cm long and 3 cm wide. Each cone contains 40 nut-like

seeds In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be sown, which may include seed and husk or tuber. Seeds are the ...

. Seeds are on average 8 mm long. Only about 15% (at most) of the seeds in the cones are fertile. Ripe cones are purple, just like those of ''P. sibirica''. Seed development and production are very poor in the putative hybrids, indicating that

introgression Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Introg ...

occurs very slowly or does not occur beyond the first filial generation. File:Pinus pumila × sibirica pine cone (hybridized).png, 1 year old dormant ''Pinus pumila'' × ''P. sibirica'' cone File:Pinus pumila and pinus pumila x p. sibirica cone comparison1.png, ''Pinus pumila'' (left) and ''Pinus pumila'' × ''P. sibirica'' (right) cone File:Pinus pumila × p. sibirica cones on Pinus pumila.jpg, Pine cones 1 month after breaking

dormancy Dormancy is a period in an organism's Biological life cycle, life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolism, metabolic activity and therefore helps an organism to conserv ...

(on ''Pinus pumila'') File:Pinus pumila × P. sibirica immature cone.jpg, Immature cone from ''Pinus pumila'', it is speculated that this megastrobilus was pollinated by a ''Pinus sibirica''

Distribution and habitat

''Pinus pumila'' × ''P. sibirica'' naturally occurs in the Baikal region of

Siberia Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states ...

(

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

) where ''P. pumila'' and ''P. sibirica'' ranges overlap, that is

Irkutsk Oblast Irkutsk Oblast (; ) is a federal subjects of Russia, federal subject of Russia (an oblast), located in southeastern Siberia in the basins of the Angara River, Angara, Lena River, Lena, and Nizhnyaya Tunguska Rivers. The administrative center is ...

, some parts of

Yakutia Sakha, officially the Republic of Sakha (Yakutia), is a republics of Russia, republic of Russia, and the largest federal subject of Russia by area. It is located in the Russian Far East, along the Arctic Ocean, with a population of one million ...

and

Buryatia Buryatia, officially the Republic of Buryatia, is a republic of Russia located in the Russian Far East. Formerly part of the Siberian Federal District, it has been administered as part of the Far Eastern Federal District since 2018. To its nort ...

. At altitudes of 2,000 to 2,100 m ( timberline), Japanese stone pine and dwarfed, sterile Siberian stone pine occur together. This increases the chances of hybridization between the two species. In the depression near Chortovo Lake
51°29'N 103°35'E
, the ''Pinus pumila'' × ''P. sibirica'' trees possess the intermediate traits compared with parental species, whereas on the slopes, they acquire a creeping form and can only be distinguished from ''P. pumila'' by their large, purple cones.

References

{{Taxonbar, from=Q111753607 pumila sibirica Interspecific plant hybrids Flora of Irkutsk Oblast Plant nothospecies

Description

Distribution and habitat

See also

References