Iris sikkimensis

It has a slender, gnarled rhizome, which has the fibrous remains of old leaves on the top.[1][3][4] It forms clumps of plants.[3]

It has pale green,[1][4][2] or light green leaves,[3] that can grow up to between 10–20 cm (4–8 in) long (at flowering time),[1][2] and between 1.2 and 2 cm wide.[4][2] After flowering, they extend up to between 30–45 cm (12–18 in) long.[1][2] They are linear, erect,[3] ensiform (sword shaped),[1][4] and semi-deciduous.[3]

It has a slender stem, that can grow up to between 10–15 cm (4–6 in) tall.[2][5][6] The stem appears in April,[3] from a tuft of 4 reduced Basal leaf leaves.[1][4]

The stem has pale green, lanceolate spathes (leaves of the flower bud). They are (scarious) membranous, in the top third of the leaf and along the edges.[1][4][2]

The stems hold 2 or 3 terminal (top of stem) flowers,[1][4][2] blooming between March and April.[3]

The flowers come in shades of lilac or purple, with a darker mottling.[2][6][5]

It has a deep purple, trigonal,[1] 3.5–5 cm (1–2 in) long perianth tube,[4][2] and a 1.2–2 cm long pedicel.[1][4]

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'.[7] The falls have an obovate (narrower end at the base) shaped blade,[1] they are 6.2 cm (2 in) long and 2.5 cm wide.[2] The haft (or part of the petal beside the stem) is wedge shaped and white with purple blotching,[1][4] or marbling.[3] In the centre of the petal is a white beard with orange tips.[1][3] The erect standards are oblong, 5 cm long and 2 cm wide.[2] They are lighter in colour to the falls, pale mauve,[2] or lilac,[1] with a fainter mottling of a darker shade.[1][4][2]

It has narrow, deep purple styles,[1][4] with faint stripes,[2] or pale at the edges,[1] and are 2.5 cm long.[2] The style branch has triangular crests.[1] It has pale violet filaments, bi-lobed stigma and creamy white anthers.[1][4]

It also has a green ovary, that is 2 cm long, mottled and striped purple.[1][2]

After the iris has flowered, it does not produce a seed capsule or seeds.[2]

It is sometimes commonly known as 'Sikkim Iris'.[1]

It is pronounced as (Iris) EYE-ris (sikkimensis) sik-im-EN-sis.[8]

The Latin specific epithet sikkimensis refers to the region of Sikkim (Indian Himalayas) where the iris was found.[9]

Mr William Rickatson Dykes had received this plant originally from Mr. Barr (a plant collector with Messrs. Barr. & Sons,[2]) in about 1906, and was labelled Iris kamaonensis caulescens.[1] He then published and described the iris as Iris kumaonensis var. caulescens. 4 years later, he changed his mind after raising the plant from seed in his garden. He thought that it was a distinct species in its own right.[2]

It was then published and described by William Rickatson Dykes in his book 'The Genus Iris' (Gen. Iris) on page134. in 1913,[10] or 1912.[11][12]

It is similar in form to both Iris hookeriana and Iris kemaonensis, but the range of both irises does not spread as far as the Himalayas.[3][2] Due to the fact that Iris sikkimensis does not set seed, it has thought to be more of a hybrid species between the two.[12][1][3] The lack of seed production has also meant it is thought to be extinct in the wild.[2] It is also very rare in cultivation, specimens have been lost in Indian herbaria and botanical gardens. No plants are found in the UK as well.[2]

It was verified by United States Department of Agriculture and the Agricultural Research Service on 9 January 2003, then updated on 1 March 2007.[11]

It is listed as an 'unresolved name' in The Plant List.[13]

Iris sikkimensis is an accepted name by the RHS, it was also last listed in the 'RHS Plant Finder' in 2010.[14]

It is thought to be native to temperate Asia.

It is hardy, and can survive winter frosts. It can also tolerate moisture during the winter. But prefers to have a dry period during the summer.[3]

A specimen of the iris can be found in 'The Arboretum and Botanical Garden' of the University of Bergen in Norway,[16] and it can also be found in University Botanic Gardens of Ljubljana in Slovenia.[17]

Like many other irises, most parts of the plant are poisonous (rhizome and leaves), and if mistakenly ingested can cause stomach pains and vomiting. Also, handling the plant may cause a skin irritation or an allergic reaction.[18]

• Liberty Hyde Bailey Hortorium. 1976. Hortus third.
• Mathew, B. 1981. The Iris. 68.

• Image of the iris in flower in the Himalayas
• Has illustration of the Iris from Dykes, W.R., The Genus Iris on page 134
• Data related to Iris sikkimensis at Wikispecies