stellar_visceras favoriter

Something unusual, I have never seen this species before. Found by @quickanddirtygardens in a small patch of old growth forest near the Oregon coast away from any trails. Growing singly on the ground, near, but not on wood.

Stipe on mature specimen 19 cm long! By 1 cm wide. Hollow interior, bulbous base. Seems like an Agrocybe as far as I can guess. At the Mushroomexpert.com key it fit best with A. firma. However, it was growing close to, not on wood, not in clusters and as far as I can tell there is no record of the species for the west coast in any local key or book. The stipe is also more than two times as long as the top range for that species. The spores (20 of them measured tediously and carefully by @stellar_viscera) were also too large for that species, measuring 9-12 x 6-7.8 microns. Spores are in range for A. putaminum, but the stipe length is still 2x longer than the range given for that species, and the cap seems darker/less yellow than the description.

Slight yellowing of stipe with KOH. Slides of spore print included with an Agaricus (top) for color comparison. They are a warm brown. I am drying the specimen and may have it sequenced through the Oregon Mycological Society. I welcome any species suggestions.