Which Peziza did I find on horse dung in Humboldt County, California, USA? The size was small, around 2 cm across.

Spores smooth, measuring 
(15) 15.2 – 16.9 (17) × (7) 7.7 – 8.9 (9) µm
Q = (1.8) 1.85 – 2 (2.2) ; N = 17
Me = 16 × 8.3 µm ; Qe = 1.9

Paraphyses septate, diameter
4.5 – 5.27 (5.3) × (3.8) 3.9 – 4.1 (4.2) µm
Me = 4.7 × 4 µm ; N = 12

Asci measure
289.3 – 376.3 × (15.4) 15.43 – 17.88 (17.9) µm
Q = 18.3 – 22.48 (22.5) ; N = 5
Me = 320.5 × 16.3 µm ; Qe = 19.6

ITS sequence: TCGCAGACcaTCAACACCCCATTGTCTACCATTACCACGTTGCTTCCACTGGACAGGCCCGGCCCCTCTTGCTTCTTCATTGAAGGGAGGGGGTCTAGGCCCTCTGGCCAATTTGACCTTAAAAATCAAATAGCTGGGGAGTGCCGGTGGATGGCCCCACCTTAAAACAAAAAAACAAAACTCTAAAGAAGAAATATTTGTCTGAACCACCTGTTTTATAACATGAAAAACATTATAAAACTTTCAACAACGGATCTCTAGGCTCTTGCATCGATGAAGAACGCAGTGAAATGCGATACGTAATGTGAATTGCAGAATCTCGTGAATCATTGAATCTTTGAACGCACATTGCGCCTTATGGTATTCCATAAGGCATGCCTGTCTGAGCGTCAGCTCCCCCCCACTCAAGCACTTTTTTTCTTAAAACCAAAATCGTGCTTGGATTGTTTTGGATGAGCGGCTGTCAAAAGCCGCTGTTCATAAATTCATTGGCAGTATGGTTTGTTCCTTTTCCAGGCTGAGCGTGATAAATTTTTTACACTTATACCGTTCAATATTGGAGGCATCGTACTCGCCCTTAACCCACAATATTTATTTGGGTGACCTCAGATCAGGTAGGGATACCCGCTGAACTTAAG