The irises have fleshy-like roots very similar to a day lily (Hemerocallis).

Most bulbs in the subgenus are found in the Himalayas and Yunnan region.

[4] They come in a range of colours between pale bluish lavender and deep reddish purple.

The blade has an orange-yellow central ridge that becomes white or purple at the apex.

[8][4] Iris decora was found in 1832 on grassy hillsides on plateaus, open stony pastures, and cliffs at 2800–3100 m above sea level.

[4] In Sichuan, Xizang (Tibet), Yunnan, Bhutan, N India and Nepal of the Western Central Himalayas.

[8] A white-flowered form from Yunnan region has been described as Iris decora var.

[8] It was found in 1909, in North Burma, Thailand, Tibet and the province of Yunnan and Sichuan (in China).

[1][9] It was named after Sir Henry Collett (1836–1901), who collected plants in most of those regions.

[10] It has been found growing in various habitats, including wood edges, clearings, shrubby areas,[11] and sunny grasslands.

It was found at 2,200–3,700 metres (7,200–12,100 ft) above sea level, in the provinces of Sichuan and Yunnan in China.

[12] It normally has a single mauve flower (about 3 cm) with bearded fall and is marked with white.

[13] A recent discovery, it was described by Henry John Noltie and K.Y.Guan in 1995 in the New Plantsman 2: 137,[16] and was collected from N.W.

[8] It has three long-tubed purple to dark-violet flowers, which are about 5 cm across, and has a short subterranean stem.