Iris humilis

Iris humilis
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Monocots
Order:	Asparagales
Family:	Iridaceae
Genus:	Iris
Subgenus:	Iris subg. Iris
Section:	Iris sect. Psammiris
Species:	I. humilis
Binomial name
Iris humilis Georgi
Synonyms[1]
Iris dahurica Herb. ex Klatt Iris flavissima Pall. Iris flavissima subsp. transuralensis Ugr. Iris humilis f. foliata Kuntze Iris rupestris Salisb. Joniris humilis (Georgi) Klatt

Iris humilis is a plant species in the genus Iris. It is also in the subgenus of Iris and in the Psammiris section. It is a rhizomatous perennial, with a wide distribution range from Europe to Russia to China, via Mongolia and Kazakhstan. It has sword-shaped leaves, a short stem and yellow flowers with an orange beard. It is cultivated as an ornamental plant in temperate regions.

It once had Iris arenaria as a synonym or as a subspecies. It is a yellow dwarf iris only from central Europe. In some sources it is still listed as a subspecies of Iris humilis.

Iris humilis is very similar in form to Iris mandshurica (another Psammiris species), which leaves curve to one side, but it is a shorter plant.^[2]

It has thick creeping rhizome,^[3][4][5] which is branched,^[4] and about 1 cm in diameter.^[6] The rhizome has the remains of last seasons leaves on the top.^[2]

It has bluish-green,^[2][4] gray-green,^[7][8] or light glaucous green,^[9][10] sword shaped or lanceolate,^[3] basal leaves.^[6][7] They can grow up to 5–10 cm (2–4 in) long,^[8][9][10] and 0.2–0.7 cm wide,^[9][11][12] They have incurving tips,^[9][12] and they disappear in summer, after flowering.^[10]

It has a simple dwarf (or short stem),^[13][14] that can grow up to between 5–25 cm (2–10 in) tall.^[15][16][17]

The stems have 2–3 spathes (leaves of the flower bud), which are lanceolate and are (scarious) membranous at the top of the leaf.^[4][9] They have short,^[4] 7.5mm long pedicels (flower stalks).^[9]

The stems hold between 1 and 3 flowers,^[18][19][11] in late spring,^[4][12][14] between April and June.^[9][13][19] The flowers only last for a day,^[19] but they sometimes repeat the display.^[13]

The vanilla scented,^[19] flowers are 3–4 cm (1–2 in) in diameter,^[10][12][19] come in shades of yellow,^[17][19][20] including bright yellow.^[9][16][18]

The flower buds are normally green, that have a slight tinge of bronze.^[9]

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'.^[6][21] The falls are oblong shaped, and 35 mm (1 in) long and 1.2 cm wide.^[9] They are veined brown or purple brown.^[7][10][20] They have a central orange beard.^[12][15][18] The shorter,^[9][11] standards are 30 mm (1 in) long and 0.3 cm wide.^[9] The standards are not erect and this gives the flower a flattish appearance.^[11]

It has a 1 cm long ovary and a 0.5 cm long, funnel shaped perianth tube.^[9]

It has styles that are shorter than the petals,^[11] about 2.5 cm long, which have short narrow crests.^[9]

The anthers are cream with green-black edging and the pollen is greenish coloured.^[9]

After the iris has flowered, in August,^[4] it produces an elliptical seed capsule,^[2] which is about 3 cm long.^[9] The capsules dehisce (split open), below the apex.^[9] Inside the capsules, are wrinkled, light brown,^[2] or brown,^[4] pyriform (pear-shaped) seeds.^[9] They have flat creamy-white aril (or appendage).^[9]

As most irises are diploid, having two sets of chromosomes, this can be used to identify hybrids and classification of groupings.^[21] It is normally published as 2n=22.^[10][11][17]

There has been several counts, over the years including 2n=27, Krogulevich 1978, 2n-24, Sokolovskya & Probatova, 1986, 2n=28, Starobudtsev & Mironova, 1990, 2n=28, Malakhova, 1990, 2n=28 Malakhova & Markova, 1994. As Iris flavissima 2n=22, Doronkin.^[15] This shows two separate entities.^[15]

Since Iris arenaria has a count of 2n=22,^[22] this means that Iris flavissima is a synonym of Iris arenaria and 2n=27 or 2n=28 are the true counts of Iris humilis.

It is pronounced as (Iris) EYE-ris (humilis) HEW-mil-is.^[16]

It has the common name of sand iris.^[7][16][23] Although this name normally refers to Iris arenaria, which was formerly once thought to be a subspecies of Iris humilis, it is now a separate species in its own right.^[22] Iris humilis is also known as low iris,^[2][24] and yellow iris.^[3][13][24] Note, that Iris pseudacorus is also commonly known as the 'yellow flag' or 'yellow iris' as well.

It is known as Sand-Schwertlilie (meaning sand iris) in Germany.^[25]

The Latin specific epithet humilis refers to low growing or dwarfish.^[8][26]

It was first published and described by Johann Gottlieb Georgi in 'Bemerkungen einer Reise im Russischen Reich' (Bemerk. Reise Russ. Reich) Vol.1 page196 in 1775.^[23][27][28]

Georgi described from specimen plants from near to Lake Baikal, (it was called originally Iris flavissima).^[28] This is now classified as a synonym of Iris humilis.^[1]

It was also published by Karl H. Ugrinsky in 'Fedde's Report. Spec. Nov., Beihefte' Vol.14 in 1922.^[15]

In 1808, Bieberstein called a plant (from the Caucasus mountains) Iris humilis, in 'Fl. Taur.-Caucas' Vol.1 on page 33. It was later changed (due to Georgi's earlier publishing) and re-classified as a synonym of Iris pontica Zapal.^[15]

It was verified by United States Department of Agriculture and the Agricultural Research Service on 4 April 2003, then updated 2 December 2004.^[23] It is an accepted name by the RHS.^[29]

It is native to a wide distribution area, including temperate regions of Asia and Europe.^[6][10][23]

It is found in Europe,^[19][20] within the countries of Austria,^[9][10][11] Czechoslovakia,^[10][11] Hungary,^[10][11][18] and Romania.^[10][11][23] However, some or most of these plants could be Iris arenaria, which also has a distribution area in central and eastern Europe.

It is found within the Siberian region,^[17][18][23] of the Russian Federation,^[13][17][20] in the states of Buryatia, Chita, Irkutsk, Magadan, Primorye and Tuva.^[23] It is also found in Kazakhstan (formerly part of Russia).^[23]

Within Asia, it found in China,^[4][5][29] within the Chinese provinces, of Heilongjiang, Jilin, Nei Monggol, Ningxia and Xinjiang,^[23] It is also found in Mongolia,^[13][17][23] and Japan.^[2][4][29]

It is listed with Iris glaucescens, Iris lactea, Iris ruthenica, Iris sibirica, Iris tenuifolia and Iris tigridia being found in the Altai-Sayan region (where Russia, China, Mongolia and Kazakhstan come together).^[30]

It grows in calcareous sandy and stony (or rocky) areas,^[7][9] including (mountain and hill) slopes,^[5][6] meadows,^[5][6] steppes,^[3][5] and on the edges of birch forests,^[3][5] or pine forests,^[2] and beside river banks.^[3]

They can be found at an altitude of 200–1,500 ft (61–457 m) above sea level.^[9]

The iris is rare in various regions,^[5][7][11] especially in European Russia and Ukraine.^[11]

It is listed in the Red Book of Omsk and Tyumen regions (of Siberia).^[2][4][5]

Many populations of Iris humilis exist in protected reserves including, Azas, Baikal-Lensky, Baikal, Barguzinsky, Sokhondinsky and Ubsunur.^[2][5]

It is hardy to between USDA Zone 1 and Zone 6.^[11][16] It survives in Siberia, so is cold resistant.^[2]

It prefers to grow in well-drained soils,^[8][18] it prefers soils containing sand.^[7][19]

It can tolerate mildly acidic or mildly alkaline soils (PH levels between 6.1 and 7.8),^[16] including those with lime.^[19]

It can tolerate positions in full sun or partial shade.^[16][19]

It has average water needs during the growing season,^[16]

The leaves can be damaged by rust fungi.^[4]

It can be grown in rock gardens,^[2][8] including rock screes,^[18] but needs plenty of space.^[9]

It is rarely grown in the UK.^[14] To grow in the UK, William Rickatson Dykes recommends to plant the iris, on a 5 cm layer of sand, over garden soil with added leaf mould (or compost).^[9]

In 1812, it was grown in gardens near Moscow.^[28] It was then tested at botanic gardens in St. Petersburg, Barnaul, Novosibirsk and Chita.^[2]

It can be propagated by division (of the rhizome), or by seed growing.^[9][16]

In the wild, some habitats generate poor seed and vegetative propagation.^[4]

The plant needs to be hand pollinated (in the UK) to create seed.^[9]

Seeds are collected from the dry pods/capsules, when the seeds are ripe.^[16]

Seeds need cold stratification, to germinate. They germinate very slowly. In the lab, seeds do not exceed a germination rate of 30%.^[4]

Seeds should be sown in trays, in a cold frame or unheated greenhouse.^[16]

Germinated seedlings, can produce flowers in the second year of growth.^[9]

Iris humilis cultivars include; 'Borzeana', 'Dahurica', 'Flavissima', 'Flavissima Orientalis', 'Flavissima Phylospatha', 'Stolonifera' 'Transuralensis' and 'Umbrosa'.^[15]

Like many other irises, most parts of the plant are poisonous (rhizome and leaves), if mistakenly ingested can cause stomach pains and vomiting. Also handling the plant may cause a skin irritation or an allergic reaction.^[16]

The rhizomes can be used as part of a Tibetan herbal medicine to regulate menstruation. A powdered form of the rhizome can be used for sepsis and infections.^[3]

• Aldén, B., S. Ryman & M. Hjertson. 2009. Våra kulturväxters namn – ursprung och användning. Formas, Stockholm (Handbook on Swedish cultivated and utility plants, their names and origin).
• Czerepanov, S. K. 1995. Vascular plants of Russia and adjacent states (the former USSR).
• Mathew, B. 1981. The Iris. 39–40.
• Tutin, T. G. et al., eds. 1964–1980. Flora europaea.
• Wu Zheng-yi & P. H. Raven et al., eds. 1994–. Flora of China (English edition).

• Media related to Iris humilis at Wikimedia Commons
• Data related to Iris humilis at Wikispecies