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.
It has short rhizome with a few branches.[1] [2] Below is thick roots.[3] On top of the rhizomes are the brown, fibrous remains of last seasons leaves, surrounding the new leaves.[1] [2] [3]
It has grey-green, sword-shaped and slightly curved leaves.[1] [2] [3] They grow up to 22- long and 1–2 cm wide.[1] [2] [3] They do not have any mid-veins.[1] [2] [3] The leaves are generally short than the flower stems.[4]
It has flowering stems that can grow up to 25- long.[1] [2] [3] [4] [5] The stems have between two and five branches.[1] [2] [3]
The plant is very similar in form to Iris dichotoma but only smaller.[4]
The stems have 3–5 green, spathes (leaves of the flower bud), which have membranous margins.[1] [2] [3] They are 2.5- long and 7–8 mm wide.[1] [2] [3] The bracts are similar in size to Iris dichotoma.[4]
The stems (and branches) hold between two and four flowers, between June and August.[1] [2] [3] But normally in June.[1] [2]
Leading from the spathes are stiff, pedicels (or peduncles), that are between 3and long.[1] [2] [3]
The flowers are 4.5- in diameter,[1] [2] [3] and come in shades of pale blue,[3] blue-purple,[1] [2] purple,[4] [5] or violet.[3] [4] [5] 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).[3] Although this is now classified as a synonym of Iris subdichotoma.
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'.[6] The falls are oblanceolate, and 4 cm long and 7cm (03inches) long.[1] [2] [3] The falls have a central yellow crest.[5] The standards are narrow and oblanceolate, and 3 cm long and 4 mm wide.[1] [2] [3]
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.[1] [2] [3] The styles branches have narrowly triangular lobes.[1] [2] [3] It also has filaments that are longer than the anthers.[1] [2]
After the iris has flowered, it produces a cylindric seed capsule,[3] between July and September, that is 5- long and 1 cm wide.[1] [2] [3] It has six longitudinal ribs.[1] [2] [3] The capsule when ripe, splits a third of the way down, releasing the seeds.[1] [2] [3] [4] The seeds are 7.5–8.5 mm wide, maroon-brown and have a small wings.[1] [2] [3] [4]
In 2006, 13 species of Iris, including Iris subdichotoma, Iris delavayi and Iris cuniculiformis were studied for a cytological analysis of the chromosome counts.[7]
In 2007, the chromosomes of Iris dichotoma, Iris domestica (Belamcanda chinensis) and Iris subdichotoma were also studied.[8]
As most irises are diploid, having two sets of chromosomes, this can be used to identify hybrids and classification of groupings.[6] Iris subdichotoma has a count of 2n=42.[7]
It has the common name of 'Zhongdian iris'.[2] [9] [10] 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.[3]
The Latin specific epithet subdichotoma refers to Iris dichotoma (Also known as the Vesper Iris). 'Dichotoma' means forked in pairs or having 2 branches.[11] It is very similar in form to Iris dichotoma but smaller.[4]
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.[1] [12]
It was verified by United States Department of Agriculture Agricultural Research Service on 4 April 2003 and then updated on 29 September 2008. Iris subdichotoma is an accepted name by the RHS.[13]
It is native to temperate regions of Asia.
It has been found in Chinese province of Yunnan,[5] [1] [10] [14] in China.[12]
It has been found on Haba Snow Mountain,[4] and beside the Yangtze River.[1]
It grows in grasslands, on open hillsides or on banks or slopes beside rivers.[1] [2] [3]
It grows at altitudes of between 1800and above sea level.[2] [3] [10]