Endemic Plants: Special Ones from the Wenatchee Mountains

Thompson’s clover (Trifolium thompsonii)

Endemic plants are those found only in a limited geographic area.  The Wenatchee Mountains of Chelan and Kittitas Counties have the greatest concentration of endemics found in Washington as well as being one of the top areas for endemics in the US.  The map below was compiled by Joe Arnett, Rare Plant Botanist with the Washington Natural Heritage Program.  The dots show locations for endemic species, with the Wenatchee Mountains in the map center, outlined in gray.

Several factors may account for this concentration of uncommon, even rare, species.  The Wenatchee Mountains lay just south of the furthest advance of the continental ice sheets and many areas did not have alpine glaciers either, so some species found refuge in the area.  The mountains were isolated enough for new species to develop without contact with their relatives.  These mountains also have the largest areas of ultramafic rocks (serpentine and peridotite) in the state.  Soils derived from these rocks have high levels of particular minerals that are toxic to most plants, leading plant species to evolve that could tolerate the challenging conditions.

Wenatchee Mountain desert parsley (Lomatium cuspidatum) surrounded by serpentinite

Derby Canyon Natives is located in the heart of the Wenatchee Mountains and it has been my pleasure to seek out and enjoy many of our endemics.  Some are rare enough to be federally or state listed as threatened or endangered species, including Wenatchee checkermallow (Sidalcea oregana var. calva), Wenatchee larkspur (Delphinium viridescens) and showy stickseed (Hackelia venusta). This year I’ve become involved in restoration efforts with the Wenatchee checkermallow.

 Wenatchee checkermallow (Sidalcea oregana var. calva)  Photo by Joe Arnett

Other endemic species in this area, although uncommon, are fun to search for and beautiful to behold.  Tweedy’s lewsia (Cistanthe tweedyi) may be the most famous of this lot, and I’ve discussed it before.  I’ll suggest several others for your search, should you be so inclined:

• Thompson’s clover (Trifolium thompsonii) – a tall clover with large, vermillion flower heads. Look for it up Swakane Canyon growing near the eastern edge of Ponderosa pine habitat.
• Yellow-white larkspur (Delphinium xantholeucum) – flowers are creamy white on 24”+ stalks.  Look for it further up Swakane Canyon along the road, or on Burch Mountain.
• Longsepal globemallow (Iliamna longisepala) – a large, bushy wildflower to 5’ tall with rose to lavender hollyhock-like flowers.  I find it in patches up Swakane as well as in draws in the Wenatchee foothills.
• Wenatchee Mountain desert parsley (Lomatium cuspidatum) – a low-growing serpentine endemic, with dense gray-green foliage and burgundy flowers. Look for it wherever fine serpentines are found! (try Wedge Mountain or Miller Peak)
• Columbia valerian (Valeriana columbiana) – clusters of bright white flowers borne above blue-green leaves, usually in rocky areas within the forest at mid elevations in the mountains.  You can find it on Tumwater Mountain or up Derby Canyon.

Yellow-white larkspur (Delphinium xantholeucum)

Longsepal globemallow (Iliamna longisepala)

Columbia valerian (Valeriana columbiana)

Have fun searching!