Iris tigridia is a plant species in the genus Iris, it is also in the subgenus Iris and in the section Pseudoregelia. It is a rhizomatous perennial, from Kazakhstan, Russia, Mongolia and China. It has dark green or greyish green, grass-like leaves, a short slender stem and a single (or rarely 2) flowers that are either violet, dark blue, blue-purple, dark purple, mauve, lilac, lavender, or light purple. It is cultivated as an ornamental plant in temperate regions.
Description
It has small compact rhizomes. Which are brown, yellow or white, fibrous. Underneath the rhizome are numerous fleshy, secondary roots, which are between 3 and 4 mm wide. On top of the rhizome are the dense, brown, or dark brown, fibrous remains of last seasons leaves. It creates small tufted plants.
It has dark green, or greyish green leaves, that can grow up to between long, and between 1.5 and 6 mm wide. At the time of flowering, they are long, and between 1.5 and 2 mm wide. They then elongate to the final height of up to 30 cm tall. They are grass-like, they can be erect and linear, or slightly curved. They do not have a midvein, but have an acuminate apex (pointed) tip. This form separates them from Iris potaninii. In mild temperate areas, they are evergreen (lasting through the winter).
It has a slender stem, that can grow up to between tall. Sometimes, the stem seems to only just appear above ground.
The stem has 2, yellow-green, (scarious) membranous, spathes (leaves of the flower bud). They are lanceolate and between long, with a pointed tip.
The stems hold 1, (or rarely 2,) terminal (top of stem) flowers, blooming between April and May, normally in May.
The flowers are in diameter, come in shades of violet, dark blue, blue-purple, dark purple, mauve, lilac, lavender, or light purple. The flowers have darker spots, veining or mottling.
Like other irises, 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'. The falls are obovate, and long, and 1–1.5 cm wide. It has in the centre of the petal, is a white patch, and a beard, with blue-white, or white hairs, tipped with yellow, or yellow hairs. The erect, or tilting outwards, standards are oblanceolate, and long and 0.4–0.7 cm wide. They are darker shade than the falls.
It has a 5 mm long pedicel, and 2 cm long perianth tube, that widens out at the top.
It has 2.3–2.5 cm long styles, that have triangular crests. It has blue pollen, and a long, green ovary, that is up to 1.2 cm long. It has 1.5 cm long stamens.
After the iris has flowered, between June and July, or up to August, it produces an ovoid, or fusiform (spindle shaped), seed capsule. That is between long, and between 1.5 and 2 cm in diameter. It has a beak like top, attached to the remains of the perianth tube. Inside the capsule are roundish, or pear shaped (pyriform), seeds. They have a creamy, or yellowish white aril (appendage).
Biochemistry
In 2003, a study was carried out on the chromosome sequencing of various Irises from the Siberian region of central Asia. They sequenced the rbcL gene from some Siberian Iris species belonging to different subgenera including, Iris halophila, Iris ludwigii, Iris uniflora, Iris pseudacorus and Iris laevigata. Their results supported Brian Mathew’s classification from 1989. That Iris bloudowii, Iris humilis, Iris ivanovae, Iris tigridia, and Iris glaucescens form a cluster.
In 2011, a chromosome and karyotype analysis study was carried out on the rhizomes of Iris tigridia. It found that the chromosome number of Iris tigridia was 2n=18.
As most irises are diploid, having two sets of chromosomes, this can be used to identify hybrids and classification of groupings. It has been counted several times. Including by Doronkin in 1984. It has been counted as 2n=18, 20, 22, 24, 28, 32, 34, 38, and 40.
Taxonomy
It is written as 粗根鸢尾 in Chinese script and known as cu gen yuan wei in Pidgin.
It is also commonly known as 'thick-root iris' in China. or 'coarse roots iris'. In Russia, it is commonly known as 'tiger Iris'.
It is known as 'Bartsooxor tsaxildag' in Mongolian.
The Latin specific epithet tigridia refers to 'tigris' or tiger-like. This refers to the colour marking of the perianth, or the rather motley coloured flower of the iris.
It was first published and described (written in Latin) by Carl Friedrich von Ledebour and Alexander Andrejewitsch von Bunge in 'Flora Altaica' Vol.1 on page 60 in 1829.