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Iris subdichotoma
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. DescriptionIt 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] GeneticsIn 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] TaxonomyIt 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 habitatIt is native to temperate regions of Asia.[11] RangeIt 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] HabitatIt 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
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