Iris fernaldii, Pine Flat Road, Sonoma County, California
Range: Central California Coastal Ranges; 50 to 2,000 feet elevation
Original material: 5 miles west of Petrified Forest, Santa Rosa-Calistoga Highway, Sonoma County, California 1937
Key identifying features:
1. Long floral tube, 1½ to 3 inches
2. Top of tube funnel-shaped, petals joined above bowl in a kind of throat before separating
3. Spathes broad, enclose ovary and most of tube
4. Plants with individual stems
5. Bases of stems, leaves and spathes often show a red wine color tint
Flower color: Rich to pale yellow, cream or white petals with a yellow signal spot and pale darker yellow venation.
Habitat: Moderately to mostly shaded woodlands, usually in loose, duff-covered soil.
Comment: In colorful magazines promoting wine tourism, Iris fernaldii is sometimes called the "little yellow wild iris". "Wine country iris" would be equally appropriate, since its distribution coincides with the best wine producing regions in the coastal ranges of central California.
Evidently, unique soil and climate conditions favor both Fernald's iris and good vineyard crops. The difference is that the little yellow wild iris lives in the dappled shade of the same cool oak forests that vineyard owners clear cut so their grapes can grow in full sun.
The yellow, cream or white flower color, a pink or reddish tint on the spathes, stem and base of the leaves, a long floral tube that opens gradually above the bowl before dividing into individual petals, and a clear habitat preference for rich humis soil in shady forests are typical fernaldii traits. In Iris macrosiphon, the petals and sepals separate directly along the edge of the bowl-like swelling at the top of the floral tube.
Fernald's iris crosses readily with other native irises that live nearby, so traces of these other species often appear in local fernaldii populations (especially in edge or marginal habitats). Plants of mixed parentage (like the fernaldii x macrosiphon hybrid pictured here) tend to prefer more sun. Genes from I. fernaldii might be the source of the yellow color of some of the natural PCNI hybrids, like yellow I. macrosiphon, and the "Marin iris".