It has pale glaucous green and narrow leaves, that are slightly sickle-shaped and fade soon after blooming.

It is rarely cultivated as an ornamental plant in temperate regions, due to its needing very dry and warm summer conditions.

[2][11][12] The stem has spathes (leaves of the flower bud), that are 6 cm (2 in) long and are green but flushed with purple at the ends.

[2][7][14] The fragrant flowers,[2] (similar to Lily of the Valley scent,[3]) are 7–8 cm (3–3 in) in diameter.

[2] They have a small,[9] darker signal area,[4][12][16] of almost black purple,[3][15] and (unlike other Oncocyclus Irises) has no veining.

[5][9][11] In the middle of the falls, is a narrow row of short hairs called the 'beard', which are white, cream,[7] or yellow, tipped with purple.

[2] It has a horizontal,[2][3] style branch that is 1 in (25 mm) long and reddish,[2] or brownish-yellow,[3] with red-purple dots or spots.

[citation needed] As most irises are diploid, having two sets of chromosomes, this can be used to identify hybrids and classification of groupings.

[19] The Latin specific epithet barnumiae refers to Mrs Barnum of the American Mission at Kharput, 1887.

[21] She sent specimens of the iris to Sir Michael Foster from north-eastern Asia Minor, near Lake Urumiah (in Azerbaijan).

[23] It was also published in 1889, in 'Gardener's Chronicle' Vol.5 page 291,[24] then in Curtis's Botanical Magazine Vol.115 on tab.7050 with a colour illustration,[3][9] in and then by Baker in 'Handbook of Iridaceae' (Handb.Irid.)

[23] It stated that plants named after people (such as Rosa × toddii (Wolley-Dod in J. Bot.

[5] A specimen was collected by James C. Archibald in Iran on 23 May 1966 at 2,070 m (6,790 ft) above sea level.

[34] It was later re-classified as a form of I. barnumiae by Mathew and Wendelbo in Flora Iranica (Rechinger, K. H., edition of) Vol.112 on page35 in 1975.

[14] I. barnumiae f. protonyma (Stapf) B.Mathew & Wendelbo was published and described in 'Flora Iranica' Vol.112 on page 34 in 1975, as I. polakii f.

[4] The iris is listed as 'rare' in Iraq,[44] within the Zagros Mountains range, along with another endemic species Tragopogon rechingeri.

[46] |Although, it needs habitats that have dry summers,[4][10] it is considered one of the least demanding of the Oncocyclus section.

[6] For the UK, the iris is better grown within an alpine house,[7] within a raised bed,[47] in a sunny position.

[13] It should be filled with 1/3 old mortar rubble,[48] and loam,[7] to provide a well drained, and fertile soil,[7][13] that allows the roots to not sit in water, that would rot them.

[47] Every three years, the clumps of irises are normally divided, as the plants are highly likely to get bacterial rot if they suffer any moisture or humidity.

Some seeds need stratification, (the cold treatment), which can be carried out indoors or outdoors.

[3] Like many other irises, most parts of the plant are poisonous (rhizome and leaves), and if mistakenly ingested can cause stomach pains and vomiting.