is Pseudorhizina californica. I believe G. sphaerospora, which is a mid-western/eastern species, is now Pseudorhizina sphaerospora. The fact that the cap is fused in places and the stipe is not deeply ribbed, lead me to believe this is just an aging, gnarly G. esculenta

at least in Smith, Smith & Weber, wherein the stipe should be “distinctly fluted” in their key. Stipe alone more closely matches G. esculenta in description. But cap does not look right to me.

Brittany’s description from Ammirati, Traquair and Horgan says in part “…but typically strongly wrinkled to folded into many convolutions and appearing more or less brain-like” G. esculenta in my experience is strongly inrolled/convoluted, and less globular.

Somewhat similar to G. sphaerospora in Smith, Smith & Weber, but should have nearly spherical spores. No spores shown in this obs.

Illustation in Smith, Smith & Weber for G. esculenta also shows more convoluted lobes. Descriptions states: "…subglobosue but irregular in outline, very wrinkled to folded over all but not pitted, yellowish, yellowish brown to bay brown or darker; stipe rather short, 2.5 cm long, 1-2.5 cm thick, furfuraceous to nearly glabrous, even to somewhat wrinkled; spores 17-22 × 7-9 microns, smooth.

Key seems to be in the spore shape on this one. But if I had to guess, maybe G. sphaerospora?

I saw that observation as well, and it gave me hope!

I concur with G. esculenta….but only because Amanitarita called it on observation 66816.
Poisonous mushrooms of the northern United States and Canada By Joseph F. Ammirati, James A. Traquair, Paul A. Horgen…
describes this species as
“CAP 2-10cm, rounded or sometimes more or less flat or saddle-shaped, irregularly three- to five-lobed; sometimes yellowish to yellowish brown, more commonly light to dark reddish brown and becoming darker on drying; sometimes nearly smooth, but typically strongly wrinkled to folded into many convolutions and appearing more or less brain-like”

^

I presume that this particular specimen is hollow and has cracked open with age or handling? Most Gyromitra sp. have a more convoluted (“brainy”) surface. Gyromitra infula (image 33074) has a simpler surface. What about something like observation 65137 (Discina perlata)?

I also found a possible Gyromitra in the Seattle area today (observation 66728).

I am unfamiliar with these sort of things, outside of some Helvella!