Iris hartwegii subsp. columbiana
Tuolumne iris, Tuolumne Iris
Photo: parent species Iris hartwegii · (c) Brendan Black, some rights reserved (CC BY-SA) · licence
Family: Iridaceae · Type: Herb · Native
Conservation status: CNPS 1B.2
Iris hartwegii subsp. columbiana (Tuolumne iris) is a native California herb in the Iridaceae family, recognized by Tuolumne County endemic with cream-yellow flowers.
Tuolumne iris is a rare (CNPS 1B.2) California native perennial found in central Sierra Nevada Mountains (Tuolumne County) in dry slopes within oak woodland at elevations of 540 to 1,400 meters. Flowering in May, this plant produces pale cream-yellow flowers with gold veining, featuring a distinctive barrel-shaped perianth tube. Growing with short stems 7 to 25 centimeters tall, it emerges from a rhizome 7 to 10 millimeters in diameter. Its basal leaves are approximately 7 to 14 millimeters wide, with a distinctive reddish base. The plant's inflorescence typically bears 3 flowers, with an outer bract 9 to 15 centimeters long and 13 to 17 millimeters wide.
Identification and appearance
Key characters: 3 sympatric species; Tuolumne County endemic with cream-yellow flowers
Habitat and range
Habitat: dry slopes in oak woodland
Elevation: 540-1400 m
Bloom period
Iris hartwegii subsp. columbiana blooms May.
Conservation status
CNPS 1B.2
How to tell it apart
vs Dietes: Iris has broad petal-like style branches; Dietes has thread-like styles and flowers lasting only one day.; vs Canna: Iris has six-parted flowers with drooping sepals; Canna has asymmetric flowers with one petal-like stamen.; vs Hemerocallis: Iris has petal-like style branches opposite stamens; Hemerocallis has simple thread-like styles and six equal tepals.; vs Typha: Iris has showy six-parted flowers; Typha has dense brown cylindrical flower spikes (cattails).; vs Sisyrinchium: Iris has large flowers with drooping outer sepals; Sisyrinchium has small flat flowers with six equal tepals.
Frequently asked questions
Is Iris hartwegii subsp. columbiana native to California?
Yes. Iris hartwegii subsp. columbiana is native to California (recorded as native).
When does Iris hartwegii subsp. columbiana bloom?
Iris hartwegii subsp. columbiana blooms May.
What plant family does Iris hartwegii subsp. columbiana belong to?
Iris hartwegii subsp. columbiana is in the Iridaceae family, genus Iris.
Is Iris hartwegii subsp. columbiana rare or endangered?
Iris hartwegii subsp. columbiana carries California Rare Plant Rank 1B.2, state rank S1.
What habitat does Iris hartwegii subsp. columbiana grow in?
Iris hartwegii subsp. columbiana grows in dry slopes in oak woodland.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos · CDFW CNDDB
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.