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.

Description

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]

Genetics

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.

Taxonomy

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]

Distribution and habitat

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

Range

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]

Habitat

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]

Conservation

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]}

Cultivation

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]

Propagation

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]

Hybrids and cultivars

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

Toxicity

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]

Traditional medicine

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]

References

Sources

• 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).

External links

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