Seeds numerous, vertically compressed, in 1 or 2 rows in each chamber. 3 mm wide, dark to reddish brown, minutely wrinkled. 3 mm diameter, dull black, minutely wrinkled. North Coast southward to Santa Barbara Co., North and South Coast Ranges, Klamath Ranges, Cascade Ranges. Reproduce vegetatively from rhizomes and by seed.
Leaves die back during periods of drought or below freezing tempertatures.
Reducing disturbance aids survival of other native species and helps keep iris populations in check. In addition, there are at least 11 other native Iris species in California. However, these species are typically not weedy and do not have all of the highlighted characteristics listed for each species above. Iris missouriensis grows in montane areas, usually in moist sites, but I. douglasiana occurs more in open fields and along the coast, generally in areas that are not wet. It tends to intergrade inland in a complex pattern associated with I. macrosiphon, I. purdyi and perhaps I. fernaldii, none of which survive in wet areas.