Iris rossii is a beardless iris in the genus Iris, in the subgenus Limniris and in the Chinenses series of the species. It is a rhizomatous herbaceous perennial.

Iris rossii is pronounced as EYE-ris ROSS-ee-eye.^[2]

It is written as 小鸢尾 in Chinese script and known as xiao yuan wei in China.^[3][4]

It is known as Ehime ayame in Japan,^[5] and written as えひめあやめin Japanese script.^[6][7]

It has the common name of Long-tail Iris in China.^[4][8][9]

The Latin specific epithet rossii refers to John Ross (1842-1915), a Protestant missionary from Scotland, who lived in north-east China. John Gilbert Baker named the iris in his honour. After he had collected several specimens of the iris and sent them to Mr Baker.^[10] Ray Desmond (Editor)Of British And Irish Botantists And Horticulturalists Including Plant collectors, Flower Painters and Garden Designers (1994)&pg=PA595 thmPzIltAV8C, p. 595, at Google Books</ref>

It is an inhabitant of dry sloping banks in the province of Sching-king, in Northern China, where it was gathered in flower on April 27, 1876, ^[11]

It was first published and described by Baker in 'Gardeners Chronicle' Vol.8 page809 in 29 December 1877.^[1][12]

It was later published in 'Gartenflora' Vol.27 page382 in 1878, 'La Belg. Hort.' Vol.28 page89 in 1878 and the 'Journal of the Linnean Society of London' Vol.17 p387 in 1880.^[11]

From the notes of Isabella Bird Bishop on 29 April 1894, she explored the valley either side of the River Han in Korea. She found various plants and flora. Including; Acanthopanax ricinifolia, Rhus vernicifera, Actinida pueraria and Iris rossii.^[13]

Originally, Iris rossii was thought to be only found in the Chinese north-eastern part, of the Korean Peninsula, but it was discovered first in Hojo within Ehime Prefecture in Japan. It was then found in other regions of Japan including; the prefectures of Saga, Oita, Miyazaki, Yamaguchi, Hiroshima and Okayama. It was also found in the forest of Nishimachi, Numata.^[14]

Between June and November 1990, the flora of vascular plants and vegetation were studied in the protected area of Hofu City within Yamaguchi Prefecture, Japan, it was classified as Vulnerable (on the IUCN Red List of Threatened Plants) as well as Calanthe discolor.^{[15] [16]}

In 1995, it was classified as Vulnerable. It had become a threatened species, due to plant hunting, changing of land use and habitat loss. It was found within grassland under scattered pine trees, which have been used for compost, fodder and timber production.^[17]

In 2002, it was classified as Endangered (EN) in Kumamoto Prefecture in 2002.^[5]

In 2012, it was studied by isolating flavonoids including an anthocyanin and C-glycosylflavones, and xanthones from the flowers and leaves. After the study, a specimen of Iris rossii was given to the herbarium of the National Museum of Nature and Science, Japan^[18]

It was verified by United States Department of Agriculture Agricultural Research Service on 4 April 2003.^[4]

As most irises are diploid, having two sets of chromosomes. This can be used to identify hybrids and classification of groupings.^[19] It has been counted several times, 2n=32, Kurita, 1940, ^[3][11] and 2n=34, Lee, 1970.^[11][20]

Like many other irises, most parts of the plant are poisonous or toxic (rhizome and leaves), if mistakenly ingested, it can cause stomach pains and vomiting. Also handling the plant may cause a skin irritation or an allergic reaction.^[2]

Iris rossii is hardy in the US and the UK, but is rare in cultivation.^[21]

It likes to grow in well drained and nutrient rich soils.^[22]

It prefers positions in full sun but it is shade tolerant.^[2][17]

It is also very drought-tolerant and could be suitable for xeriscaping.^[2][16]

It could be planted in alpine scree slopes and in rock gardens.^[16]

Iris rossii does not like being propagated by [Division (horticulture)|division]], as it takes along time to re-grow feeding roots, after transplanting.^[22][16]

Therefore propagation from the seed is preferred.^[22][16]

It is thought to be a zoochory plant because ants like the seeds and carry them away to new positions. Allowing the plant to form new colonies elsewhere.^[22][16]

Iris rossii is similar in form to Iris ruthenica.^[23]

It has slender, tough, reddish-brown, creeping rhizomes.^{[3][10][24][16]} Under the rhizome, are long secondary roots growing into the soil, looking for nutrients and water.^[10][16] They have the yellow-brown remnants (sheaths or fibres) of the previous seasons leaves, at the base of new leaves.^{[24][3][10][16]}

It has narrow, linear leaves, acuminate (ending in a point, grass-like), that are between 4–10 cm (2–4 in) long and 0.2–0.5 cm (0–0 in) wide.^[3][10][24] They have between 2-4 veins.^[3] They then elongate after flowering, up to 30 cm (12 in) long.^[24][22]

It has dwarf, short stems,^[18][16] (or scapes) between 10–30 cm (4–12 in) long.^{[3][23][20][21][22][11][14][2][10]} It has one or two terminal (at the top of the stem) flower,^[3][10] in spring to early summer,^[2] between April,^[14][16] and May.^[3][22]

It has 2 or 3 lanceolate (lance-like) between 4–7 cm (2–3 in) long and 0.1–0.4 cm (0–0 in) wide, spathes (leaves of the flower bud).^[3][10]

The small flowers are 3.5–4 cm (1–2 in) in diameter,^[3][10][18] and come in a range of shades of purple and violet, but there are occasionally white forms as well.^{[3][10][20][21][22][11][14][2][16]} The white form is only found in Korea.^[22]

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'.^[19] The falls are obovate, 3cm long and 0.8-1.2cm wide, it is marked with white spots, veins or white signal area. It has a white/yellow centre section.^{[3] [20][11][10]} The standards are erect or slightly angled, measuring 2.5cm long and 0.8cm wide.^{[3] [10]}

It has a long perinath tube of 5-7cm,^[23][10] a 1cm long pedicel, slender 1.5cm long stamens, 1cm long ovary and 2cm long style branches (which are a similar colour to the petals).^[3]

After the iris has flowered, it produces a globose (spherical) seed capsule between June and August.^[3][16]

Iris rossii is native to temperate areas of Asia.^[4]

It is found in Japan,^[16](Honshu, Shikoku and Kyushu^[24]) Korea and China (Liaoning and Manchuria^[21]).^{[4][10][24][20][23][21][3][18]}

Saga, Oita, Miyazaki, Yamaguchi, Hiroshima, Okayama. There is several places of own cloth in the forest of Nishimachi, Numata, but area appointed to natural monument is one place. All tend to be frequent in good place per positive in sparse grove place of dirt pine wood. ^[14]

It grows in meadows (and grasslands) at forest margins, on sunny hillsides.^{[22][3][15][16]} and clearings within pine woods.^[14]

At altitudes of 100m above sea level.^[3]

Iris rossii forma Alba was found in the deciduous forests of Korea, by Dr Yong No Lee and then published in the 'Korean Journal of Botany' vol.17, No1, p33-35 in 1974. It had white flowers streaked with yellow, instead of violet, found on other forms.^[16][11]

But this was later declared a synonym of Iris rossii.^[1]

Mathew, B. 1981. The Iris. 81. Waddick, J. W. & Zhao Yu-tang. 1992. Iris of China. Wu Zheng-yi & P. H. Raven et al., eds. 1994–. Flora of China

Media related to Iris rossii at Wikimedia Commons Data related to Iris rossii at Wikispecies