Iris subdichotoma

Iris subdichotoma
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
Order: Asparagales
Family: Iridaceae
Genus: Iris
Subgenus: Limniris
Section: Lophiris
Species: I. subdichotoma
Binomial name
Iris subdichotoma
Y. T. Zhao
Synonyms

Iris subdichotoma f. alba .G.Shen & Y.T.Zhao[1]

Iris subdichotoma is a species in the genus Iris, it is also in the subgenus of Limniris and in the Lophiris section (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 between 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 between 25–40 cm (10–16 in) long.[2][3][4][5][6] The stems have between 2-5 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 7-8mm wide.[2][3][4] The bracts are similar in size to Iris dichotoma.[5]

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

Leading from the spathes are stiff, pedicels (or peduncles), that are between 3–4 cm (1–2 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 2 pairs of petals, 3 large sepals (outer petals), known as the 'falls' and 3 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 to September, that is 5–6 cm (2–2 in) long and 1 cm wide.[2][3][4] It has 6 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]

Biochemistry

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'.[2][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 Vesper Iris). 'Dichotoma' means forked in pairs or having 2 branches.[13] It is very similar to Iris dichotoma but smaller.[5]

It was first published and described by Yu Tang Zhao in 'Acta Phytotaxonomica Sinica' (Acta Phytotax. Sin. in Beijing) Vol.18 Issue1 page57 in 1980.[2][5][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,[2][4][5][6][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 to 2,700 m (5,900 to 8,900 ft) above sea level.[2][3][4][12]

References

  1. 1 2 "Iris subdichotoma Y.T.Zhao is an accepted name". theplantlist.org (The Plant List). 23 March 2013. Retrieved 19 March 2015.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 subdichotoma "Iris subdichotoma" Check |url= value (help). flph.org (Flora of Pan Himalayas). Retrieved 19 March 2015.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 "Zhongdian Iris". tl.swewe.net. Retrieved 20 March 2015.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 "FOC Vol. 24 Page 307". efloras.org (Flora of China). Retrieved 19 March 2015.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 Franco, Alain (29 November 2013). "(SPEC) Iris subdichotoma Zhao". wiki.irises.org (American Iris Society). Retrieved 19 March 2015.
  6. 1 2 3 4 5 "Iris summary" (pdf). pacificbulbsociety.org. 14 April 2014. Retrieved 23 November 2014.
  7. 1 2 Austin, Claire. "Irises A Garden Encyclopedia" (PDF). worldtracker.org. Retrieved 29 October 2014.
  8. 1 2 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. Retrieved 20 March 2015.
  9. ↑ 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.
  10. ↑ "Zhongdian iris". scires.datatang.com. Retrieved 19 March 2015.
  11. 1 2 3 4 5 6 429047 "Taxon: Iris subdichotoma Y. T. Zhao" Check |url= value (help). ars-grin.gov (Germplasm Resources Information Network). Retrieved 19 March 2015.
  12. 1 2 3 "Zhongdian Iris". zhiwutong.com. Retrieved 19 March 2015.
  13. ↑ 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.
  14. 1 2 439147-1 "Iridaceae Iris subdichotoma Y.T.Zhao" Check |url= value (help). ipni.org (International Plant Names Index). Retrieved 19 March 2015.
  15. ↑ "Search the RHS Horticultural Database". www.rhs.org.uk. Retrieved 20 March 2015.
  16. ↑ "2nd Yunnan joint research report". bgtym.org. Retrieved 19 March 2015.

Other sources

Mathew, B. 1981. The Iris. 205. Waddick, J. W. & Zhao Yu-tang. 1992. Iris of China.

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