Summary:
Features include 1) a white covering formed on Helvella species, the covering becoming pinkish brown to cocoa brown, 2) an anamorph that is common, and forms two kinds of asexual spores, and a teleomorph that is rare (with asci and ascospores), 3) ascospores that are less than 25 microns long (with acute not apiculate ends), smooth, and 2-celled, and 4) perithecia that are waxy, and white to pale buff. The current name in the online Species Fungorum, accessed September 6, 2017, was Hypomyces cervinus Tul. & C. Tul. but the current name on MycoBank, accessed the same day, was Hypomyces cervinigenus Rogerson & Simms.
The type is from WA. Distribution and records include BC, WA, Europe (including Estonia, Germany, Netherlands, Norway), Japan, Kazakhstan, (Poldmaa), and CA (MykoWeb). There is a collection from AK at the University of Washington.
Fruiting body:
a soft, tomentose to finely pubescent mould-like covering, "white, becoming pinkish to cream-buff", powdery when old, parasitizing stem and cap tissue of the host, (MykoWeb), subiculum white, not changing color in KOH, texture hyphal; the anamorph in nature "starts as a white mycelium that during the production of chlamydospores turns into powdery cocoa-brown layer that usually expands over the whole fruitbody of the host", (Poldmaa), subiculum "white, at first loose and cottony, becoming compacted into a mat" (as perithecia appear), perithecia separate to densely compacted in patches up to 1 square centimeter, "usually with base immersed in host tissue", when fresh white and translucent with a waxy appearance, when dry and when old light yellow, buff, or amber, (Rogerson)
Microscopic:
two types of asexual SPORES: 1) aleuriospores 13.5-17.5 microns in diameter including ornamentation, round, spiny, thick-walled, "joined to a secondary, thin-walled, more or less hemispheric cell", in deposit the aleuriospores are pinkish buff, 2) conidia: 14.0-25.5 x 4.0-5.0 microns, cylindric-elliptic, smooth, thin-walled, contents granular or with one to several oil droplets, some centrally septate; ascospores and perithecia rare, according to Rogerson & Simms spores (15)18-22(26) x 2-4(5) microns, subfusiform, smooth, at maturity typically 1-septate, the ends pointed, not apiculate, (MykoWeb), CONIDIUM (6)12-22 x 3-5(6) microns, "fusiform, equilateral, with basal hilum absent", 0-1(3)-septate, conidiogenous locus "with no proliferation observed, forming 1-3 conidia that are held in heads", CONIDIOGENOUS CELLS "usually borne directly from aerial or submerged hyphae", by 1(2) in a verticil, 55-140 microns long, 2-2.5 microns wide at base, proliferation not observed, CONIDIOPHORES hardly or not differentiated from aerial hyphae; ASCOSPORES 14-22(26) x 3-4(5) microns, fusiform or naviculate [boat-shaped], smooth, "ends nonapiculate, the upper end usually acute and the base obtuse", "1-septate (with the septum often obscured) or aseptate, septum median or submedian"; ASCUS (100)115-125(140) x 2-3(4.5) microns; with apex thickened (about 2 microns), penetrated by a pore; PERITHECIA "gregarious to scattered, semi-immersed in the subiculum", (165)250-350(385) x (130)165-200(265) microns, "buff or light yellow, KOH reaction absent", perithecial wall 10-12 microns wide, perithecial papillae 45-100 microns high, 45-60(75) microns wide at base, "tip obtuse, of hyphal texture, with cells not forming differentiated regions", surface cells 1-2 microns in diameter; SUBICULAR HYPHAE 2-3 microns wide, loosely interwoven (at first) or densely compacted (when perithecia are formed), (Poldmaa), ASCOSPORES 22(26) x (1.5)2-4(5) microns, "fusiform to spindle-shaped, sometimes curved", (usually acute at the apices but often with lower end obtuse), smooth, colorless, cytoplasm usually vacuolate, 1 or 2 celled, septum often obscured, lower cell often narrower and smaller than upper cell, septum median or submedian, spores obliquely uniseriate; ASCUS 8-spored, filling the centrum, "frequently protruding from the ostiole", (100)115-125(142) x 2-3(4.5) microns, long and linear, thin-walled except at obtuse apex, apex forming a thickened cap, 1-2 microns thick, with a distinct pore (staining with cotton blue in lacto-phenol, not staining in Melzer''s reagent) visible in young asci, contracted at base, then swollen and foot-like, pore obscured as spores mature, the acute apex of upper spore protruding into the pore; PERIPHYSES 15-20 x 2 microns, filamentous, "obtuse at apex, curved upward, lining the ostiolar canal", "apical paraphyses present in early stages, disappearing as asci form"; PERITHECIUM (165)250-350(385) x (132)165-200(265) microns, spherical-ovate to spherical-papillate, frequently collapsing laterally, papilla obtuse to truncate, 45-90(100) x 45-62(75) microns, wall 10-12 microns thick, irregularly pseudoparenchymatous in face view, cells thin-walled, irregularly elongate and prosenchymatous up to 15 x 6 microns, with 4-5 layers in longitudinal section, "becoming filamentous and parallel at the papilla", "papilla with an outside layer of irregular cells covered by a zone of amorphous, small, contracted, hyphal cells creating a waxy appearance"; SUBICULUM hyphae less than 3 microns wide, branched, colorless, septate, "disappearing as perithecia become compacted", (Rogerson)
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