2. Iris L. (iris, flag,
fleur-de-lys)
Plants with rhizomes. Aerial stems sometimes very short, mostly erect or ascending
(decumbent in I. brevicaulis), circular in cross-section. Leaves
appearing 2-ranked or basal, flat. Inflorescences unbranched or sometimes
few-branched, of 1 to several clusters of flowers subtended by reduced,
leaflike bracts, the clusters with 1–3 flowers enclosed by a pair of
spathelike, herbaceous or papery bracts. Flowers with stalks 3–80 mm long.
Perianth with a well-developed tube at the base, the sepals and petals much
different in size and position, the 3 sepals spreading, reflexed, or arching
downward and mostly obovate to spathulate, the 3 petals erect to spreading,
linear to obovate. Stamens usually not fused basally. Styles with the 3 style
branches enlarged and petaloid, positioned over the sepals and concealing the
stamens, 2-lobed at the tips, the stigmatic area at the base of these lobes and
covered by a flap of tissue. Capsules oblong, nearly circular in cross-section
to bluntly 3- or 6-angled. Seeds flattened, with a fleshy to gelatinous aril
(except in our crested species). Two hundred to 300 species, North America,
Europe, Asia, northern Africa, cultivated worldwide.
The genus Iris is far more variable morphologically than is accounted
for in the preceding description. It also has a long history of cultivation for
ornamental, cosmetic, and medicinal purposes that potentially dates to ancient
Egyptian times (Mabberley, 1987). Essential oils present in the rhizomes of
some of the bearded species have a strong smell of violets (tincture of
orrisroot) and are still used commercially to simulate the smell of violets in
some perfumes and cosmetic powders. Mathew (1981) presented the most detailed
summary of the numerous cultivated species, their characteristics, and their
origins. In conjunction with plant breeding and domestication, a specialized
terminology has evolved for the perianth that is variously used in much of the
literature. The sepals are referred to as falls, with the narrow,
stalklike bases called hafts. The sepals may be variously flat, ridged,
crested, or bearded. The petals are referred to as standards, and their
narrowed bases are usually called claws. Regardless of relative
position, it is the sepals that always have the stamens and petaloid style
branches overlaying them.