Iris minutoaurea is a beardless iris in the genus Iris, in the subgenus Limniris and in the series Chinenses of the genus. It is a rhizomatous herbaceous perennial of eastern Asia, native to China and Korea. It has been naturalized in Japan. It has long grassy-like leaves, short stem and bright yellow or pale yellow flowers. It is cultivated as an ornamental plant in temperate regions.
Iris minutoaurea | |
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Iris minutoaurea from the Korean National Arboretum | |
Scientific classification ![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Monocots |
Order: | Asparagales |
Family: | Iridaceae |
Genus: | Iris |
Subgenus: | Iris subg. Limniris |
Section: | Iris sect. Limniris |
Series: | Iris ser. Chinenses |
Species: | I. minutoaurea |
Binomial name | |
Iris minutoaurea | |
Synonyms[1] | |
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Iris minutoaurea can sometimes be mistaken for Iris henryi (another yellow flowering Chinese iris). But they differ is sizes of pedicel (flower stalk) and perianth tube. Iris henryi has a short perianth tube and long pedicel, while with Iris minutoaurea it is the other way around.[2]
It has a yellowish brown, slender, wiry, rhizome,[3][4] measuring about 2 cm (1 in) long and 0.5 cm (0 in) wide,[5] that produces many branches and stolons.[6][7] This branching habit forms clumps of plants.[8][4][9] In autumn, the roots (under the rhizomes), produce small nodules.[10] These are used to fix nitrogen, from the soil.[11]
It has grassy, linear, ribbed, 5–16 cm (2–6 in) long and 0.2–0.7 cm (0–0 in) wide leaves.[10][9][7] They appear in early March, they then elongate after flowering up to 40 cm (16 in) long, reaching a maximum height by June.[3][5][7] This elongating leaf habit is also shared by Iris koreana.[12]
It has a very short, slender flowering stem, only 7–10 cm (3–4 in) long.[13][10][9] It has one terminal (at the top of the stem) flower,[3] in spring to early summer,[8][4] in April or May.[6][5][10]
It has 2 lanceolate (lance-like) 4–5 cm (2–2 in) long and 0.5–0.1 cm (0–0 in) wide, spathes (leaves of the flower bud), that are acuminate (ending in a point).[6]
The small flowers come in yellow shades. Between bright yellow and pale yellow.[9][2][14] The flowers are 2.5–3 cm (1–1 in) in diameter.[3][5][4] Which can be compared to the size of a quarter.[15]
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'.[16] The drooping obovate (egg-like) falls, measuring 2.2 cm (1 in) long and 0.8 cm (0 in) wide, have brown or purple marks (dots or lines) on the hafts and in the centre of the petal.[13][5][10] The smaller, paler (in colour) narrow, upright standards are between 1.5 cm (1 in) long and 0.3–0.4 cm (0–0 in) wide,[6] with brown/purple petal stalks.[10][9][2]
It has a slender, 1.5–2.5 cm (1–1 in) long perianth tube.[6][3] It has slender 1.5–2.5 cm pedicel (flower stalk), 1 cm long stamens and yellow-brown anthers. It has 1 cm (0 in) long 0.2–0.3 cm (0–0 in) ovary and 1.5 cm (1 in) long 0.3 cm (0 in) wide, style branches similar in colour to the standards.[6]
After the iris has flowered, it produces a globose (spherical) seed capsule between June and July.[6][5]
The effect of forcing date and temperature on growth and flowering of Iris koreana and Iris minutoaurea has been examined in 2007.[17]
As most irises are diploid, having two sets of chromosomes. This can be used to identify hybrids and classification of groupings.[16] It has been counted twice, 2n=22, Simonet, in 1934; syn. Iris savatieri Nakai and 2n=26, Lee in 1970.[8] It is normally listed as 2n=22.[6][18]
It is written as 小黄花鸢尾 in Chinese script and known as xiao huang hua yuan wei in China.[6][19]
It is written as 금붓꽃 in Korean script.[20]
It has the common names of small yellow-flower iris in Chinese English.[19]
The Latin specific epithet minutoaurea refers to the combination of 2 Latin names, minuto refers to very small (or minute) and aurea refers to yellow.[21] Making 'Small yellow blossoms'.[22]
It was originally published as Iris minuta by Franchet and Savatier in 'Enumeratio Plantarum in Japonia Sponte Crescentium' 2: Vol.42 page521 in 1877.[6][8][23]
It was later illustrated as Iris minute in Curtis Botanical Magazine Issue 8293 in 1910.[3]
Later, Iris minuta was regarded as a synonym of 'Iris minutoaurea and first published and described by Tomitaro Makino in the 'Journal of Japanese Botany', (Shokubutsu Kenkyu Zasshi) from Tokyo Vol.17 in 1928.[24]
Iris minutoaurea is an accepted name by the RHS.[25]
It was verified by United States Department of Agriculture Agricultural Research Service on 9 January 2003.[19]
Iris minutoaurea is native to the temperate regions of eastern Asia.[19][9] It has a wider geographical area than Iris odaesanensis.[5]
It can be found on the Korean Peninsula, and in Liaoning Province of northeastern China.[26][27][28]
It is also found on Gyebangsan Mountain in South Korea.[20]
It has been naturalized in Japan.[4][5][19]
It grows on forest margins and grassy hillsides.[6]
It has been listed in the flora of vascular plants in the Chilgapsan Provincial Park of Korea.[26] It was listed as 'least concern' on the Red List of vascular plants according to IUCN on Mt. Gilsangsan in Korea.[29] Also listed as 'least concern' on the list of Jeju Island in Korea.[27] It has also been listed as growing on Deokjeokdo.[30]
In Liaoning, China, it was listed as an endemic vascular species, along with Acontium faurieri, Artemisia chienshanica, Betula ceratoptera, Caragana litwinowii, Iris kobayashii, Phragmites australis and others.[31]
Iris minutoaurea has been cultivated in UK, but it is rare,[32] and considered difficult to grow.[13] It is also rare in Europe.[5] It has also, been cultivated in the US but is thought difficult to get it to bloom.[33] It is much easier to grow in Japan, where it has been cultivated for many centuries.[25][14][4]
It is hardy to Zone H2 (which means hardy to −15 to-20 °C (5 to −4 °F [34]), in Europe.[3][35] Although, it has survived in temperatures as low as −29 °C in France.[5] It will be difficult to get to flower in areas of cool summers.[4]
It can be grown in a bulb frame to survive a cold winter or over-watering.[13][5]
It likes to grow in humus-rich, well-drained, neutral to acidic soils.[5][4][10]
It prefers positions in full sun but may tolerate part shade.[5][9]
It does not like positions that get a lot of water,[13][5] preferring well drained, rock gardens and scree-like slopes.[5][10][9]
It can be propagated by division.[5] They need to be divided when ever the clumps of plants get congested and it stops blooming.[15]
It is best planted in September or March.[10] The iris is untouched or undamaged by slugs.[5]
Taxon identifiers |
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