Although few wildflower species were blooming, the late August / early September trip to the Siskiyous still held some floral highlights for me. One was encountering and photographing this narrow-range endemic, Epilobium oreganum, or Grants Pass willowherb.
Epilobium oreganum only occurs in Darlingtonia californica fens on serpentine soils in northwest California and southwest Oregon. It is one of five co-occurring taxa of concern in these specialized habitats, discussed in the multi-agency report Conservation Agreement for Hastingsia bracteosa, Hastingsia atropurpurea, Gentiana setigera, Epilobium oreganum, and Viola primulifolia subsp. occidentalis and serpentine Darlingtonia wetlands and fens from Southwestern Oregon and Northwestern California (PDF). I think I’ve now seen all of these in flower.
Epilobium oreganum is a thin-stemmed species growing up to 1m (3 ft.) tall among the pillars of Darlingtonia‘s tubular leaves. Small flowers, perhaps an inch (~2.5cm) across, eventually develop into slender capsular fruits that are 4.5cm long (~2 in.). Though it shares a similar specific epithet, it is not to be confused with Epilobium oregonense, a much more widely-distributed species.
CalPhotos contains a number of images of Epilobium oreganum, including some habitat and whole-plant images.