Fungi classified in the Hysteriaceae Chevall. (Chevallier 1826) are defined by a specialized ascocarp termed the hysterothecium (Clements 1909). Hysterothecia are dense, persistent carbonaceous structures, distinctly navicular in outline, and bear a pronounced longitudinal slit running the length of the long axis of the fruitbody. Hysterothecia may be capable of opening partially to reveal a lenticular, disk-like hymenium or closing tightly in response to relative humidity, suggesting that some may be perennial, capable of spore discharge over prolonged periods (Lohman 1933). They can be immersed to erumpent or entirely superficial, solitary or gregarious, ellipsoid to greatly elongated, and are sometimes branched, triradiate or borne on a subiculum (Zogg 1962). In vertical section, hysterothecia are globose to obovoid, typically with a thick three layered peridium, composed of small pseudoparenchymatous cells, the outer layer heavily encrusted with pigment and often longitudinally striated on the surface, the middle layer lighter in pigmentation and the inner layer distinctly thin-walled, pallid and compressed (Barr 1987). The hamathecium is composed of persistent cellular pseudoparaphyses, often borne in a gel matrix, with tips darkened or branched at maturity to form an epithecium. Bitunicate asci are borne in a basal layer and at maturity are typically clavate to cylindric, bearing eight ascospores, overlapping biseriate, ranging from hyaline to dark brown, obovoid, clavate, ellipsoid or fusoid. Ascospores are highly diverse in septation and range from didymospores to phragmospores to dictyospores, at times surrounded by a gel coating, and often show bipolar asymmetry (Barr 1987). The family has been monographed by Zogg (1962). Current classification of the Hysteriaceae (Eriksson 2006) includes the following genera: Hysterium Pers. : Fr., Hysterographium Corda, Gloniopsis De Not., Gloniella Sacc., Glonium Muhl. : Fr., Farlowiella Sacc., and Hysterocarina Zogg, to which has been recently added Actidiographium Vassiljeva. The genera Hysteroglonium Rehm ex Lindau, Hysteropatella Rehm and Pseudoscypha Reid & Piroz., are tentatively included in the Hysteriaceae by Eriksson (2006). In addition to these, the genera Encephalographa Massal. (Renobales & Aguirre 1990; Tretiach & Modenesi 1999), Graphyllium Clem. (Shoemaker & Babcock 1992), and Hemigrapha (Müll. Arg.) R. Sant. ex D. Hawksw. (Diederich & Wedin 2000) were included by Kirk et al. (2001). Both coelomycetous pynidial states (e.g., Hysteropycnis, Aposphaeria) and dematiaceous hyphomycetous anamorphs (e.g., Coniosporium, Septonema, Sirodesmium, Sphaeronaema and Sporidesmium) have been described (Lohman 1931, 1933, 1934). Hysteriaceous fungi are panglobal in distribution, having been reported from Japan (Amano 1983), China (Teng 1933), the Russian Far East (Vasilyeva 1999a, b, 2000), South Africa (Lee & Crous 2003; van der Linde 1992), Argentina (Messuti & Lorenzo 1997, 2003; Lorenzo & Messuti 1998), Costa Rica (Checa et al. 2007), North America (Lohman 1933, 1937) and Europe (Zogg 1962). Although primarily lignicolous or corticolous, recently a saxicolous / terricolous and apparently lichenized species has been described from Tasmania (Kantvilas & Coppins 1997).

Barr (1987): “Ascomata immersed erumpent or superficial, short ellipsoid to greatly elongated, sometimes branched or tri-radiate, in vertical section globose, ovoid or obovid, separate or gregarious, apex rounded or plane, opening by longitudinal slit, reclosing or remaining open & exposing hymenium; surface smooth or longitudinally striate, subiculum present at times; peridium wide, composed of three layers of small pseudoparenchymatous cells, the outermost thin & often heavily encrusted with dark pigment, the middle wider, lighter brown, the innermost thin, pallid, of more compressed cells. Hamathecium of narrowly cellular pseudoparapyses, in granular matrix, tips darkened at maturity forming the epithecium. Asci bitunicate, basal, clavate or cylindric. Ascospores hyaline or light to dark brown, obovoid, clavate, ellipsoid or fusoid, one or several septate or muriform; wall smooth foveolate or verruculose, at times surrounded by gel coating; contents granular; overlapping biseriate in the ascus. Anamorphs where known coelomycetous or hyphomycetous (Coniosporium, Septonema, Shpaeronema, Sporidesmium). Saprobic or hemibiotrophic on woody substrates, cosmopolitan. The classical family grouping has been divided into two (Zogg, 1962): the Hysteriaceae, now placed in the Pleosporales, & the Lophiaceae, in the Melanommatales, under the earlier name Mytilinidiaceae. The presence of elongate ascomata that open by a longitudinal slit is not solely a prerequisite of the Hysteriaceae, so some care must be taken to note the consistency of the peridium. In this family it is firm, quite thick, three layered, composed of small pseudoparenchymatous cells that are heavily pigmented externally. The relationship of some members seems to be with the Cucurbitariaceae, as Luttrell (1953) suggested or with the Pleosporales. The ascospores of species in Gloniopsis are quite similar to those found in the Lophiostomataceae. The most recent study of genera & species is that of Zogg (1962). Lohman’s (1937) paper on Glonium in southeastern North America & his earlier detailed examination of cultural features in several representatives of the family (Lohman 1932, 1933, 1934) repay thorough reading. Taxa of the genera Farlowiella, with one-celled brown ascospores that have a small hyaline basal cell, & Gloniella, with several-septate hyaline ascospores, have not yet been reported from temperate North America. Hysterocarina is known only from the original specimens of H. paulistae Zogg from Brazil”.

Wehmeyer (1975): “The genera of the Ascomycetes having ascocarps which open by the formation of an elongate slit or a radiate rupture have been a troublesome group showing relationships to both the Discomycetes & the Pyrenomycetes. The various genera have been transferred back & forth between such families as the Phacidiaceae, Ostropaceae, Tryblidiaceae, Lophodermataceae, Hysteriaceae & Lophiostomataceae. The two chief families usually placed in the Hysteriales are the Lophodermataceae & the Hysteriaceae. The Lophodermataceae have sunken ascocarps with membranous walls & are obviously related to the Discomycetes, whereas the Hysteriales have superficial fruitbodies with carbonaceous walls & show a relationship to the Lophiostomataceae & the Dothideales. The Hysteriales occur as saprophytes on dry substrata such as weathered wood, bark,, resin, etc. The ascocarps are superficial on the substrate & in most genera are ellipsoid to elongate, linear or branched, with a coriaceous wall & open with an elongate slit. In a few genera the ascocarp is conchate, in the shape of a mussel shell set vertically on edge, with a slit like opening along the upper edge. Zogg (1962) placed these conchate genera in a separate family, the Lophiaceae & gave a monograph for these two families. The asci are bitunicate, cylindric to lavate & the ascospores are various in color & septation. The conidial states are of the two general types. Pycnidial states with small globose to ellipsoid or fusoid spermatia are found in most genera. Hilitzer (1929), who monographed the order, placed all these pycnidial states in a form genus Hysteropycnis. Lohman (1931 – 1938), who has published on both the ascus & conidial states o these fungi, placed these pycnidia in various form genera. The second type of conidial state consists of septate colored conidia borne singly or in chains on clumped conidiophores, of the form genera Septonema, Sirodesmium & Papulospora."

I. Fruitbody a black carbonaceous ascomata, short ellipsoidal to long cylindrical, without a prominent keel, typically borne above or sessile upon the substratum, rarely +/- immersed. Fruitbody typically with a sunken longitudinal cleft that extends down the length of the fruitbody (a hysterothecium).

A. Ascospores pedicellate amerospores, the upper pigmented & much larger than the lower, which remains un- or less-pigmented:

= Farloweilla Sacc.

B. Ascospores not as above, didymospores, the two cells more or less equal in size:

1. Ascospores hyaline, didymospores:

= Glonium Muhl. : Fr.

2. Ascospores pigmented didymospores:

= Actidiographium L.N. Vassilyeva

C. Ascospores transversely septate, phragmospores:

1. Ascospores pigmented phragmospores: 

= Hysterium Pers. : Fr.

2. Ascospores hyaline phragmospores:

= Gloniella Sacc.

D. Ascospores transversely and longitudinally septate dictyospores:

1. Ascospores pigmented dictyospores: 

= Hysterographium Corda

2. Ascospores hyaline dictyospores.

= Gloniopsis De Not.

II. Ascospores pigmented dictyospores (as in D, 1. above), but hyterothecia borne within the substrate, with a cristate longitudinal apex instead of a sulcus. Neotropical.

= Hysterocarina Zogg