A unique race of Hartweg's Iris is restricted to southern California's montane yellow pine forests in the San Bernardino, San Gabriel and San Jacinto mountains. It probably represents the southernmost populations of a once continuous distribution - now isolated from its nearest Sierra Nevada relatives since the end of the last Ice Age.
Other than its geographical separation, in most features I. hartwegii australis differs little from it relatives in the Sierra Nevada mountains. The spathes tend to be wider (average 7.9 mm, versus 5.2 mm for the species), the pedicle below the ovary shorter (average 28 mm, versus 47 mm), and except in the central eyespot, the color palette of the flower is limited to shades from purple to pale lavender.
During his term as president of the Society for Pacific Coast Native Iris, Richard Richards organized an expedition for Society members to the San Bernardino Mountains. His photos from 2006 (below) illustrate the appearance and habitat of Iris hartwegii's southern race.
Photo set and notes by Richard Richards, 2006
The Society's 2002 Minitrek to find Iris hartwegii australis in its natural habitat in Southern California took place shortly following serious local forest fires and several seasons of significant drought. Visitors had to search hard to find just a few blooming iris.
In June, 2006, I again visited stands of this southern race of the Sierra, or Hartweg's Iris at the same sites around Barton Flat, in the San Bernardino Mountains. Adequate winter snows and rain had resurrected them. Here are some photos of what I saw. This is how they typically grow in a bed of yellow pine needles, like the other races of Sierra Iris found at intermediate elevations along California's Sierra Nevada mountains.
Southern Hartweg's Iris - Irus hartwegii pinetorum, San Bernardino County, California. Photos by Richard Richards, 2006. To see larger copies, click on the following links: Top row - [L], [C], [R]; Bottom row - [L], [C], [R].
The top three photos deal with the same "clump", such as clumps are in most cases. As you can guess, I liked the color very much. The fourth photo shows an attractive plant flowering in the reddish violet-to-purple range.
The bottom-middle scene provides a nice contrast between two different clones growing closely together. And the last photo shows that occasionally I. hartwegii australis can develop into something of a loose clump. This is as clumpy as I have ever seen it.