Hymenoscyphus albidus  

Anamorph: not known.
Teleomorph: ascomata apothecia, the initials formed from the upper mesophyll and degraded epidermal tissue in blackened areas of petioles, breaking through the substratum surface to become superficial at maturity; scattered or in clusters of 2-4. Apothecia to ca 2 mm diam when fresh, shallowly cupulate with a short stalk, the margin slightly raised above the hymenial surface, pure to ivory white or pale cream when fresh, drying to buff or pale yellow-brown, smooth or finely downy below, narrowing gradually to a short stalk, composed of hyphae 4-6 µm diam oriented almost parallel to the surface, sometimes extending as short obtuse hairs 10-15 x ca 2µm in size. Stalk to ca 2 mm in length and 500-750 µm diam, slightly enlarged and blackened at the base due to partial sheathing by the host epidermal tissue, composed of closely packed parallel hyphae 3-4 µm diam. Hymenium concolorous with the surrounding excipular tissue. Interascal tissue of copious simple unbranched paraphyses 3-4 µm diam, slightly enlarged towards the apex, usually 3-septate, not immersed in gel. Asci 60-90(-95) x 7.3-9.8 µm, cylindrical to cylindric-clavate, croziers not present, thin-walled, short-stalked, the apex obtuse with a small J+ apical ring, 8-spored. Ascospores arranged obliquely uniseriately, (13.1-)14-17(-18.5) [mean=15.8, sd=1.26, n=40] x 3.1-4 [mean=3.5, sd=0.22, n=40] µm, cylindrical to cylindric-ellipsoidal, the apex often with a small eccentric extension, slightly inaequilateral, the basal region slightly tapered, fairly thin-walled, aseptate, sometimes becoming pale brown, without a gelatinous sheath or appendages, the contents granular when fresh.