I thought I had a white truffle but after spotting another white mass close-by sprouting small white mushrooms I was able to make a positive ID. Clitocybe sclerotoidea parasitize Helvella lacunosa (Elfin saddle) and leave behind a hard mass of mycelia tissue called a sclerotium. Light fresh garlic / spring onion fragrance. (Fragrance disappeared within hours.)
Under the moss, Douglas fir. Spicy; citrusy odor, especially after being cut. Spongy, rubbery texture. Keys to Hymenogaster utriculatus in Mushrooms Demystified, the modern name of which is Gymnoglossum utriculatus. According to that description, the spores are honeycombed, which I believe I observed but it was difficult to capture in the photo. However, MD also says utriculatus is "rare". The other option is Hymenogaster subalpinus, which is very common in this area.
Under Populus, but some Alnus around, Pinus in the area too
Doug fir associated. Nasty rotting fish smell
Deer truffle?
Collected by Gary Laursen and Keith. Mild taste. Birch present at the site.