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Iris subdichotoma
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Monocots
Order:	Asparagales
Family:	Iridaceae
Genus:	Iris
Subgenus:	Iris subg. Limniris
Section:	Iris sect. Lophiris
Species:	I. subdichotoma
Binomial name
	Iris subdichotoma; Y. T. Zhao
Synonyms
	Iris subdichotoma f. alba .G.Shen & Y.T.Zhao

Iris subdichotoma is a plant species in the genus Iris, it is also in the subgenus Limniris and in the section Lophiris (crested irises). It is a rhizomatous perennial, from Tibet and China, with pale blue, blue-purple, purple, violet or white flowers. It is cultivated as an ornamental plant in temperate regions.

Description

It has short rhizome with a few branches.^[2]^[3] Below is thick roots.^[4] On top of the rhizomes are the brown, fibrous remains of last seasons leaves, surrounding the new leaves.^[2]^[3]^[4]

It has grey-green, sword-shaped and slightly curved leaves.^[2]^[3]^[4] They grow up to 22–40 cm (9–16 in) long and 1–2 cm wide.^[2]^[3]^[4] They do not have any mid-veins.^[2]^[3]^[4] The leaves are generally short than the flower stems.^[5]

It has flowering stems that can grow up to 25–40 cm (10–16 in) long.^[2]^[3]^[4]^[5]^[6] The stems have between two and five branches.^[2]^[3]^[4]

The plant is very similar in form to Iris dichotoma but only smaller.^[5]

The stems have 3–5 green, spathes (leaves of the flower bud), which have membranous margins.^[2]^[3]^[4] They are 2.5–3.5 cm (1–1 in) long and 7–8 mm wide.^[2]^[3]^[4] The bracts are similar in size to Iris dichotoma.^[5]

The stems (and branches) hold between two and four flowers, between June and August.^[2]^[3]^[4] But normally in June.^[2]^[3]

Leading from the spathes are stiff, pedicels (or peduncles), that are between 3 and 4 cm (1 and 2 in) long.^[2]^[3]^[4]

The flowers are 4.5–5 cm (2–2 in) in diameter,^[2]^[3]^[4] and come in shades of pale blue,^[4] blue-purple,^[2]^[3] purple,^[5]^[6] or violet.^[4]^[5]^[6] Later, a white flowering form was found and then was published and named as Iris subdichotoma f. alba Y. G. Shen, in 'Acta Bot. Yunnan' Vol.26 Issue5 page492 in 2004).^[4] Although this is now classified as a synonym of Iris subdichotoma.^[1]

It has three pairs of petals, three large sepals (outer petals), known as the 'falls' and three inner, smaller petals (or tepals, known as the 'standards'.^[7] The falls are oblanceolate, and 4 cm long and 7 cm (3 in) long.^[2]^[3]^[4] The falls have a central yellow crest.^[6] The standards are narrow and oblanceolate, and 3 cm long and 4 mm wide.^[2]^[3]^[4]

It has a 2 cm long perianth tube, 2.2 cm long stamens, 1.5 long and 0.5 cm wide, fusiform (spindle-shaped) ovary and 3 cm long style branches.^[2]^[3]^[4] The styles branches have narrowly triangular lobes.^[2]^[3]^[4] It also has filaments that are longer than the anthers.^[2]^[3]

After the iris has flowered, it produces a cylindric seed capsule,^[4] between July and September, that is 5–6 cm (2–2 in) long and 1 cm wide.^[2]^[3]^[4] It has six longitudinal ribs.^[2]^[3]^[4] The capsule when ripe, splits a third of the way down, releasing the seeds.^[2]^[3]^[4]^[5] The seeds are 7.5–8.5 mm wide, maroon-brown and have a small wings.^[2]^[3]^[4]^[5]

Genetics

In 2006, 13 species of Iris, including Iris subdichotoma, Iris delavayi and Iris cuniculiformis were studied for a cytological analysis of the chromosome counts.^[8]

In 2007, the chromosomes of Iris dichotoma, Iris domestica (Belamcanda chinensis) and Iris subdichotoma were also studied.^[9]

As most irises are diploid, having two sets of chromosomes, this can be used to identify hybrids and classification of groupings.^[7] Iris subdichotoma has a count of 2n=42.^[8]

Taxonomy

It has the common name of 'Zhongdian iris'.^[3]^[10]^[11]^[12] Note; 'Zhongdian' is an older name for Shangri-La City. It is written as 中甸鸢尾 in Chinese script and known as zhong dian yuan wei in Pidgin Chinese.^[4]^[11]

The Latin specific epithet subdichotoma refers to Iris dichotoma (Also known as the Vesper Iris). 'Dichotoma' means forked in pairs or having 2 branches.^[13] It is very similar in form to Iris dichotoma but smaller.^[5]

It was first published and described by Yu Tang Zhao in 'Acta Phytotaxonomica Sinica' (Acta Phytotax. Sin. published in Beijing) Vol.18 Issue 1 on page 57 in 1980.^[2]^[11]^[14]

It was verified by United States Department of Agriculture Agricultural Research Service on 4 April 2003 and then updated on 29 September 2008.^[11] Iris subdichotoma is an accepted name by the RHS.^[15]

Distribution and habitat

It is native to temperate regions of Asia.^[11]

Range

It has been found in Chinese province of Yunnan,^[6]^[2]^[12]^[16] in China.^[11]^[14]

It has been found on Haba Snow Mountain,^[5] and beside the Yangtze River.^[2]

Habitat

It grows in grasslands, on open hillsides or on banks or slopes beside rivers.^[2]^[3]^[4]

It grows at altitudes of between 1,800 and 2,700 m (5,900 and 8,900 ft) above sea level.^[3]^[4]^[12]

References

^ ^a ^b "Iris subdichotoma Y.T.Zhao is an accepted name". theplantlist.org (The Plant List). 23 March 2013. Retrieved 19 March 2015.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa "Iris subdichotoma". flph.org (Flora of Pan Himalayas). Retrieved 19 March 2015.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z "Zhongdian Iris". tl.swewe.net. Retrieved 20 March 2015.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa "FOC Vol. 24 Page 307". efloras.org (Flora of China). Retrieved 19 March 2015.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Franco, Alain (29 November 2013). "(SPEC) Iris subdichotoma Zhao". wiki.irises.org (American Iris Society). Retrieved 19 March 2015.
^ ^a ^b ^c ^d ^e "Iris summary" (PDF). pacificbulbsociety.org. 14 April 2014. Retrieved 23 November 2014.
^ ^a ^b Austin, Claire (2005). Irises: A Gardener's Encyclopedia. Timber Press, Incorporated. ISBN 978-0881927306. OL 8176432M.}
^ ^a ^b Shen, Yun-Guang; Wang, Zhong-Lang; Guan, Kai-Yun (2007). "Karyotypes of thirteen species of Iris L. from China". Acta Phytotaxonomica Sinica. 45 (5): 601–618. doi:10.1360/aps06064. Archived from the original on 4 March 2016. Retrieved 20 March 2015.
^ Wang, Hong; Shen, Xiao-hui; Guo, Ying (March 2007). "Karyotype Analysis and Taxonomic Status of Iris dichotoma". Journal of Shanghai Jiaotong University (Agricultural Science). Retrieved 19 March 2015.
^ "Zhongdian iris". scires.datatang.com. Retrieved 19 March 2015.^{[permanent dead link‍]}
^ ^a ^b ^c ^d ^e ^f "Iris subdichotoma". Germplasm Resources Information Network. Agricultural Research Service, United States Department of Agriculture. Retrieved 19 March 2015.
^ ^a ^b ^c "Zhongdian Iris". zhiwutong.com. Retrieved 19 March 2015.
^ Smith, A.W.; Stearn, William T. (1972). A Gardener's Dictionary of Plant Names (Revised ed.). Cassell and Company (published 1963). p. 117. ISBN 0304937215.
^ ^a ^b "Iridaceae Iris subdichotoma Y.T.Zhao". ipni.org (International Plant Names Index). Retrieved 19 March 2015.
^ "Search the RHS Horticultural Database". www.rhs.org.uk. Retrieved 20 March 2015.
^ "2nd Yunnan joint research report". bgtym.org. Retrieved 19 March 2015.