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Iris douglasiana, the Douglas iris, is a common wildflower of the coastal regions of Northern and Central California and southern Oregon in the United States. It grows mainly at lower elevations and is most common in grasslands near the coast. The plant is commonly cultivated outside of its native range, and has been by humans for its strong fibers and medicinal properties.
Description
I. douglasiana is a beardless iris typical of subgenus Limniris, series Californicae. It grows from a rhizome that is typically less than a centimeter in diameter. Its leaves are about wide and may grow up to 1 meter (3 ft) long. Leaf color ranges from yellow to dark green, with a more red appearance at the base. The flowers, appearing from April to June, are usually a purplish-blue, though occasionally white or yellow flowers are found. Two or three flowers are found on each stem, which is of variable height, ranging from tall. Flowers have three nectar-producing subunits, usually exhibiting both male and female parts (a stamen and style, respectively). I. douglasiana is protandrous, meaning pollen becomes available to pollinators before the stigma matures. However, male-sterile plants have also been found in the wild. These are less common, but may be less susceptible to damage from insect larvae. During pollination, bees typically visit only one subunit of the flower. This pattern, in addition to the protandrous flowering, reduces the likelihood of self-fertilization. Flowers mature into capsules containing up to 80 seeds.
Ethnobotany
I. douglasiana has many useful properties, used primarily by Indigenous peoples such as the Pomo. However, it is not safe to consume as food and can cause severe discomfort if ingested in large quantities. Medicinal applications include use as a diuretic or laxative, to induce vomiting, or to treat infection on external wounds. Furthermore, fibers along the leaf margins can be extracted and combined to construct nets, strings, ropes, and snares. Processing the leaves requires a significant amount of time, but the resulting products are strong and flexible.