Small to large clusters (5 to ~20 mm diam) of dark brown to yellow cup-shaped apothecia (1-3 mm in diam.), bursting through the bark of dead branches of Salix in boggy habitats, often with or near the Hymenochaetopsis tabacina (willow glue). Macroscopically distinctive from other Encoelia spp. which typically have larger and less clustered apothecia lacking the distinctive margin of E. fimbriata.
Apothecia densely gregarious in clusters of up to ca. 80, arising from a common stromatic base, erumpent through bark. Disc 1-3 mm diam, concave, dark vinaceous brown, smooth. Margin incurved, whitish-fimbriate. Receptacle cupulate, narrowed below the disc, surface conspicuously furfuraceous (scaly), yellowish-brown or olivaceous. Asci 45-59 (-63) x 7-8.5(-9) μm, 8-spored, cylindric-clavate (club-shaped), narrowed at the base into a short stipe, apex slightly narrowed, truncate or truncate-rounded, pore not blue in Melzer's reagent. Paraphyses 2.8-2.2 μm diam, filiform, obtuse, sparsely septate, sheathed with mucilage in the lower part. Hymenium 50-60 μm deep. Subhymenium 10-40 μm thick, composed of hyaline (translucent) or pale brown, interwoven, vertically orientated hyphae with slightly thickened walls. Medullary excipulum a textura intricata, 30-50 μm thick in the receptacle, composed of hyphae ca. 2 μm diam, with slightly thickened, brownish walls which do not lose colour in 5% aqueous KOH or Melzer's reagent. Towards the margin these hyphae become parallel to the surface of the receptacle. Ectal excipulum a textura globulosa, 70-85 μm thick, cells 5-8 (-10) μm diam, with slightly thickened walls, irregularly arranged except near the margin, becoming separated at the surface and forming large, irregular pustules. Innermost layers greenish, surface layers brown, the pigment partly intercellular, granular, soluble in ammonia and Melzer's reagent. Towards the margin the cells are arranged in rows at a high angle to the surface and give rise to hair-like structures. Hairs 40-90 (-170) x 3.5-5.0 μm, arising from ectal cells and medullary hyphae, hyaline or basally pale brown, lanceolate (lance-shaped), usually pointed, walls thickened, often appearing thicker due to shrinkage of cytoplasm, often encrusted with granules towards the apices.
Adapted from Spooner and Trigaux (1985). "A new Encoelia (Helotiales) from Prunus spinosa in France." Transactions of the British Mycological Society 85.3: 547-552.