sauk mountain is a peak north of highway 20 around marblemount. a popular hike, the trailhead puts you relatively high and into an alpine area with pikas and marmots. the actual hike doesn't require much elevation gain to reach the summit, which affords views all over skagit valley and beyond.
although it is very close to helen buttes both in and elevation, the lichen flora is noticeably different. i'm not sure exactly what to attribute this too, but i suspect the substrate may play a role. perhaps sauk mountain gets especially cold for some reason. in any case, sauk mountain features lots of Psora nipponica, various Peltigera, Protopannaria pezizoides, Peltigera venosa, Dermatocarpon and more. Brigantiaea fuscolutea was recently collected here, at the summit on moss (Niphotrichum) over vertical rock. additionally, typical alpine lichen such as Thamnolia, Cetraria and others are common at the summit.
when hiking this trail for the first time, the Psora really stuck out to me. the other place i see them frequently is washington park, which also has Dermatocarpon (as well as lots of other cool lichens). washington park is serpentinite, an ultramafic rock that's not commonly found in washington. another spot with Psora is on cougar divide, which is on marine sedimentary rocks of the nooksack formation. sauk mountain on the other hand is mostly volcanics (the chilliwack group, 358.9-298.9 million years old), but it has some "sandstone, siltstone, shale, and minor limestone" (clastic rocks) mixed in. although the serpentinite of washington park is quite different than here, the nooksack is similar to the clastic parts of sauk mountain.
