Microglossum truncatum  

A small, smooth, hairless earthtongue growing usually in small clumps, the brownish-green or brown hymenium (fertile area) and contrasting blue-green stipe distinguish the species from closely-related M. pratense whose concolorous hymenium and stipe are uniformly blue- or gray-green. The hymenium usually occupies more than the upper half of the ascocarp, and has a slight, single groove running vertically. The species grows on soil among grass in temperate meadows without extremes of wet or dry.

Ascocarps (19-)25.4-44.3(-55) [(20-)30.2-55.5(-60)] mm high, tongue-like or clavate (club-shaped), stipitate (with stipe). Hymenium (8-)22.2-28.5(-30) × (1-)3.2-4.1(-7) [(10-) 25.3-32.3(-44) × (1-)3.1-5.2(-8)] mm, cylindrical, clavate (club-shaped), truncate(d) or lanceolate (lance-shaped), only slightly grooved vertically, glabrous (smooth and hairless), naked, brownish-green or light brown or green-brown, dark green or brownish-green when dry. Hymenium usually constituting more than the upper 1/2 of the ascocarp. Stipe (10-)15.2-20.1(-27) × 1-2.2(-3) [(11-)16.5-23.6(-29) × 1.2-3.1(-4)] mm, cylindrical, blue-green, not paler at the base. Asci (75-)85.1-98.7(-105) × (8-)8.4-9.6(-10) [(95-) 120.6-135.3(-150) × (8-)10.1-11.5(12)] μm, 8-spored, clavate (club-shaped), rounded at the apex, narrowly tapered towards the base, biseriate (arranged in two rows) above, uniseriate (arranged in a single row) below, pore bluing in Melzer’s reagent. Ascospores (14-)15.4-18.3(-20) × 4-4.7 (-5) [(17-)18.2-19.8(-21) × 4-5(5.5)] μm, hyaline (glassy/translucent), ellipsoidal to oblong, aseptate (not partitioned by septa). Paraphyses filiform (thread-like), straight, branched in basal part, some of the paraphyses branched in apical part, apical cells filiform 1-2 μm or only slightly swollen (<3 μm).

Adapted from Kučera et al. (2017). “Taxonomic divergence of the green naked-stipe members of the genus Microglossum (Helotiales)”. Mycologia 109.1: 46-54.