By: Til K. Thapa and Sangeeta Rajbhandary
Perennial herbs. Rootstock bulbous or creeping, sometimes with swollen storage roots. Stems erect, solitary or many, simple or branched. Leaves usually basal, flat, equitant, ensiform, sword shaped to linear. Bracts 2 or more, subtending 1 or more flowers. The inflorescence arranged in racemes, panicles or solitary. Flower stem branched or simple; flowers terminal, solitary or in few-flowered groups, sessile or shortly pedicellate. Perianth segments 6, connate at base with the hypanthium, forming a short to well-developed tube, dimorphic; outer 3 perianth segments (sepals) are largest, stipitate, reflexed and known as falls, usually differentiated into basal glabrous or beard claw and a lamina which may have a beard or cock’s comb-like crest or unicellular papillae or only a smooth ridge. Inner 3 perianth segments (petals) are usually smaller, suberect or reflexed and known as standard; color variation is very pronounced, either the whole flower is of uniform color or bicolor; falls are normally darker. Stamens 3, inserted at the base of the outer segments; filaments free, anther linear, basifixed. Ovary trigonous, style stout, stigmas petaloid, arching over the stamens as a flap (petal like) and 2-cleft. Capsule coriaceous, 3 or 6-ribbed, many seeded. Seeds flat or globose, arillate or non-arillate.
Worldwide ca. 300 species, mainly distributed in Asia, Europe, N. Africa and N. America (Mabberley, 2017).
Only one genus in Nepal (Iris)