IRIDACEAE

IRIS FAMILY

Elizabeth McClintock, except as specified

Perennial, bulbed, cormed, or rhizomed
Stem generally erect
Leaves generally basal (a few cauline), 2-ranked, ± linear, generally grass-like, generally sharply folded along midrib; bases overlapping, sheathing
Inflorescence: spike, raceme, panicle, ± terminal, or flowers solitary; bracts ± like leaf bases, sheathing
Flower generally bisexual, generally radial; hypanthium fused to ovary; perianth parts generally fused into tube above ovary, generally petal-like, in 2 series of 3, outer (sepals) generally ± like inner (petals); stamens 3, generally attached to sepals, filaments fused below into a tube or not; ovary inferior, 3-chambered, placentas generally axile, style 1, each of 3 branches entire or 2-branched or -lobed, petal-like or not, with stigma on under surface instead of at tip
Fruit: capsule, loculicidal
Seeds few–many
Genera in family: 80 genera, ± 1500 species: worldwide, especially Africa; many cultivated (e.g., Iris, Gladiolus, Crocus, Freesia ).

IRIS

IRIS

Douglass M. Henderson and Anita F. Cholewa

Perennial; rhizome creeping or ± tuber-like
Inflorescence: flowers 1–many
Flower: perianth parts clawed, sepals (wider, spreading or reflexed) unlike petals (generally narrower, erect); style branches ± petal-like, arching over stamens, each with flat, scale-like stigma on surface facing stamen, just below generally 2-lobed tip (crest)
Seeds compressed, pitted
Species in genus: Perhaps 150 species: generally n temp
Etymology: (Greek: rainbow, from flower colors)
Reference: [Lenz 1958 Aliso 4:1–72; Clarkson 1959 Madroño 15:115–122]
Hybrids are common, especially in I. tenax alliance; some authors lump taxa recognized here.
Horticultural information: Pacific Iris hybrids; CVS.

Introduced

I. pseudacorus L.

Rhizome 30–40 mm diam
Stem 5–15 dm, branched
Leaf 10–25 mm wide, stiff
Inflorescence: flowers many; lowest 2 bracts generally opposite, outermost 4.9–5.1 cm, 7–10 mm wide
Flower: perianth bright yellow or cream, crest area outlined by series of brown marks, tube 12–13 mm, sepals < 6 cm, petals narrowed near middle; style branches < 25 mm, crests 7–10 mm, stigmas rounded
Fruit 5–8 cm
Chromosomes: 2n=24,30,32,34
Ecology: Irrigation ditches, pond margins
Elevation: generally < 100 m.
Bioregional distribution: San Francisco Bay Area, s San Joaquin Valley
Distribution outside California: widespread e of Rocky Mtns; native to Europe