Good evening.

The litter of cottongrass (Er. vaginatum) hosts four common discomycetes now: Hyaloscypha sp., Mollisia sp., Lachnum sp. and the last one, bright yellow - i have doubt with the genus.  Here it is:

It commonly seen at wet fallen leaves, and leaf sheaths, inside the tussocks.

Apothecia cupulate, sessile, 500–850 mk in diameter, to 300 mk thick; hymenium surface bright yellow, outer surface pale yellow, slightly pubescent and when young with white velum at base; single or 2-3 in clusters.

Excipulum from ellipsoid cells with thickened walls about 10 x 5; outer surface and edge with free hyphoid elements up to  30 x 3, filled with greenish content; asci clavate, with conical tip, with crozier, with euamyloid ring, 70–85 x 8–11; paraphyses cylindrical, septated in lower part, in upper part with several round and large elongated greenish vacuole, 84 x 2.4; spores ellipsoid, without oils, with weak sheaths at the ends, 11 (10.5–12.2) x 2.8 (2.3–3.5) (n=13).?