T. mammosum (for which I’ll post an observation) is not uncommon in the Pacific Northwest on Si rock, particularly near salt water. Its spores are non-septate and spherical, in contrast to T. occidentale, which in my experience in Washington is not very common, and usually is found on wood, particularly fence posts.
2011-02-18 21:10:55 EST (-0500)
Jason Hollinger (jason)
Beautiful specimen and spores!