Spore measurements (spore print in water):

(10) 10.5 - 11.9 (14) × 6.2 - 6.9 (8.8) µm
Q = (1.5) 1.6 - 1.78 (1.8) ; N = 20
Me = 11.2 × 6.6 µm ; Qe = 1.7

Tips of paraphyses up to 6 µm wide.

I tried to figure out the species with the aid of the Otidea monograph but didn't come to any certain conclusion. My best guess is O. nannfeldtii and second one O. formicarum.

O. nannfeldtii apparently likes to grow on nutrient-rich, often calcareous soil. This place seemed to be acidic though, not nutritious.

O. formicarum typically grows on old ant hills but apparently can also grow on just needle debris. Maybe the dark warts on the outer surface speak against it? I haven't seen any pics or descriptions that include them for that species.

The last two microphotos are from a dried fruitbody in 3 % KOH.

Viktorie Halasu, 17-09-2020 00:12

Re : Small-spored Otidea

Hello,

I think the ectal excipulum (cell walls) became yellow in KOH, did you consider O. tuomikoskii? In some collections, this reaction can disappear again in ca. 20 seconds, in others it stays. Also the intensity and placement of the yellow staining is variable. In nannfeldtii the surface exudates turn reddish brown, and it should have two-layered medulla (although I have a DNA-confirmed collection of nannfeldtii with 1-layered medulla too). 

Cheers,
Viktorie