The genus Hysterium Tode
Schriften Berlin. Ges. naturf. Freunde 5: 53 (1784).

by Eric W.A. Boehm

The genus Hysterium (Clade C). A-B. Hysterium pulicare (CBS 123377 [BPI 878723], USA).  C-F. Hysterium angustatum (ANM 120 [ILLS], USA). G-K. Hysterium vermiforme (GKM 1234 [BPI 879785], Kenya). L-Q. Hysterium barrianum sp. nov. (ANM 1495 [ILLS 59908 = holotype], USA). Scale bar (habitat) = 500 μm; Scale bar (spores and asci) = 20 μm. Fig. 2 from Boehm et al. 2009b.
The genus Hysterium, the type genus of the family Hysteriaceae, is attributed to Tode, who was the first to apply the name to a group of fungi bearing a pronounced longitudinal slit, for which he gave the common name “Venusschwämme” (Tode 1784). In the initial description, Tode (1784) designated a single species, H. quadrilabiatum Tode, as the type, and in 1790, a second species, H. bilabiatum Tode was described. However, in a subsequent publication (1791), Tode excluded both species, and re-described the genus, noting “Medium hoc genus inter Pezizas & Lichenes“. Fries (1823) did not take up any of Tode’s species while sanctioning the genus, specifically excluding both H. quadrilabiatum and H. bilabiatum, noting that Tode himself (1791) had rejected these names. Although Fries (1823) did not accept any of Tode’s species, he did continue to cite Tode 1791 as the authority for the genus, thereby effectively lectotypifying Hysterium Tode : Fr. Earlier, Persoon (1801) transferred the epithet pulicaris, first proposed by Lightfoot (1777) for a variety of Lichen scriptus ß pulicaris, into what was to later become the lectotype species of the genus, namely Hysterium pulicare (Lightf.: Fr.) Pers., designated the lectotype by Bisby (1923), a species earlier accepted by Fries (1823).

The genus is characterized by pigmented versicolorous or concolorous asymmetric phragmospores, three- or more transversely-septate, with cells often constricted, especially at the median septum. Zogg (1962) recognised two morphological types within the genus. Type I is characterised by 3-septate phragmospores, and includes the versicolorous type species H. pulicare (Lightf. : Fr.) Pers., and its closely related concolorous counterpart, H. angustatum Pers., both extremely common in the temperate zones of both hemispheres. These are followed by H. vermiforme Massee, from Africa, and the much larger-spored H. macrosporum Peck, reported from North America and China (Teng 1933). Although Zogg (1962) did not accept H. hyalinum Cooke & Peck, Lohman (1934) provided legitimacy to the epithet, noting that pigmentation is delayed in the maturation of the 3-septate ascospores (Boehm et al. 2009a, b).

Type II corresponds to a different phragmospore, one in which, typically, there are five or more septa, and in which there exists a swollen cell, either just above the median septum (i.e., supramedian) or, rarely, some distance up from the median septum. Type II includes, by increasing spore length, the cosmopolitan H. insidens Schwein., the larger-spored counterpart H. sinense Teng, and the unusual H. magnisporumW.R. Gerard, 7-septate, with three of the septa crowded to each end, the two central cells much larger. The latter two species are reported from China (Teng 1933) and North America (Boehm, unpubl. data). Hysterium velloziae Henn., provisionally included by Zogg (1962), with up to 21 septa at maturity, has only been reported from Africa (van der Linde 1992). Molecular data (Boehm et al. 2009b) has recently supported a new genus, Oedohysterium E.W.A. Boehm & C.L. Schoch gen. nov. to support taxa previously classified as Hysterium, but that possess an enlarged median or supra-medial cell (see below).

An additional two species have been recently described. Hysterium asymmetricum Checa, Shoemaker & Umaña (Checa et al. 2007) from Costa Rica, has outer centrum tissues pigmented red, and 3-septate phragmospores, showing an extended basal cell. Hysterium andinense Messuti & Lorenzo has been recently described from the conifer Austrocedrus chilensis in Argentina (Messuti & Lorenzo 1997). However, molecular and morphological data (Boehm et al. 2009a, b) has placed this taxon in the Mytilinidiaceae, as Mytilinidion andinense (Messuti & Lorenzo) E.W.A. Boehm, C.L. Schoch & J.W. Spatafora, based on CBS 123562 (BPI 878737). This brings the total number of species within the genus Hysterium to ten. An additional new species was recently described in Boehm et al. (2009b), namely Hysterium barrianum E.W.A. Boehm, A.N. Miller, G.K. Mugambi, S.M. Huhndorf & C.L. Schoch.

 In Boehm et al. (2009b), we were able to secure a wide taxon sampling strategy for the genus Hysterium, including multiple isolates for seven of the eleven currently recognised species, namely: H. pulicare (1), H. angustatum (7), H. vermiforme (1), H. insidens (2), H. sinense (2), H. barrianum (2) and H. hyalinum (1). Multiple gene phylogenies indicate that the genus Hysterium is polyphyletic, along three separate lines, two within the Hysteriaceae and one, H. hyalinum, outside of the family (Boehm et al. 2009b). This implies that the evolution of pigmented phragmospores borne in hysterothecia has occurred at least three times within the Pleosporomycetidae. Sequence data indicate that Clade C contains the type species, Hysterium pulicare, as well as the closely related H. angustatum, and H. vermiforme (Fig. 1). All three taxa have 3-septate, pigmented phragmospores, corresponding to Type I. Also, within Clade C resides the newly described H. barrianum, with 9-sepate spores. None of these species has a swollen supra-median cell. Accessions of H. angustatum, originating from South Africa (CMW 20409), Kenya (GKM 243A), New Zealand (SMH 5211.0, SMH 5216) and the United States, New Jersey (CBS 123334) and Wisconsin (CBS 236.34), form a highly supported monophyletic clade with H. pulicare, collected from the United States, New York (CBS 123377). Both species possess similar pigmented 3-septate phragmospores, versicolorous in H. pulicareand concolorous in H. angustatum. Interestingly, ~10 % of the ascospores within a given hysterothecium of H. pulicare are typically found to be concolorous (Bisby 1941). Likewise, versicolorous ascospores have also been observed in H. angustatum, stated at less than ~5 % for a given hysterothecium (Lee & Crous 2003). Although ascospore size in H. pulicare may be twice that found in H. angustatum (Zogg 1962), a certain degree of overlap in spore length measurements exists between the two, and molecular data presented here and elsewhere (Boehm et al. 2009) indicate that they are closely related.

In Boehm et al. (2009b), one of the H. angustatum accessions from Tennessee (ANM 85), did not cluster with the other surveyed H. angustatum in Clade C. Instead, ANM 85 clustered with H. vermiforme from Kenya (GKM 1234). Spore measurements of ANM 85 (ILLS) were compared to the other H. angustatum accessions from the United States (CBS 123334 / BPI 878724), Kenya (GKM 243A, EA), and New Zealand (SMH 5211.0, F) which formed the other sub-clade within Clade C. All of these specimens showed remarkably little variability in their spore morphology. Additionally, no obvious differences were noted in their fruitbody morphology. This may indicate early stages of speciation within the taxon, with sequence variation preceding morphologic change. Grouping with the anomalous H. angustatum ANM 85, was H. vermiforme, a taxon known only from the original description by Massee in 1901 from West Africa (Ghana). The isolate included here (GKM 1234 / BPI 879785) originated from Mt. Kenya, Kenya, and possesses smaller spore measurements, (20-)25-28 x (4-)5-6 μm, than those given by Massee (1901), and reiterated by Zogg (1962), as (30-)35-40 x 12-14 μm. In other respects, however, BPI 879785 matches closely Massee’s (1901) original description, and we choose here to simply expand the spore measurements for H. vermiforme to (20-)25-40 x (4-)5-14 μm, rather than describe a new species. The 3-septate H. hyalinum(CBS 237.34) lies outside of the Hysteriaceae altogether. It falls in a small, isolated, but well-supported clade along with the type species of Hysterographium, namely Hg. fraxini. Since only one isolate is represented, it is premature to draw conclusions.

Molecular data also indicate that the remaining two species of Hysterium in our survey, namely H. sinense and H. insidens, are not related to the type H. pulicare and associated species within Clade C. Rather, data indicate that they belong to Clade D. As such, we proposed the new genus Oedohysterium E.W.A. Boehm & C.L. Schoch (Boehm et al. 2009b). This new genus is covered under a separate page (following). As such, we choose to provide the following dichotomous key whereby all hysteriaceous fungi, bearing transversely septate pigmented phragmospores (including Oedohysterium) are identified together, with the caveat that unrelated taxa appear in the same key.


Key to the species of Hysterium and Oedohysterium

  1. Phragmospores mainly 3-septate →  2
  2. Phragmospores concolorous, more than 3-septate, in one instance pigmented dictyospores with 1‑2 vertical septa (Od. pulchrum) →  7


  1. Phragmospores either versicolorous or delayed concolorous →  3
  2.  Phragmospores truly concolorous (sepia to dark brown in colour) →  4


  1. Terminal cell mainly remaining hyaline with inner spore cells pigmented brown (versicolorous); ascospores 20-40 x 6-12 μm; cosmopolitan →  Hysterium pulicare (Lightf. : Fr.) Pers. 
  2. Phragmospores tardily pigmented, often remaining hyaline for quite some time after discharge, but eventually becoming uniformly concolorous; 20-26(-28) x 6-8.5 μm; North America →   Hysterium hyalinum Cooke & Peck

Note: Currently recognised as Pleosporomycetidae sp. incertae sedis (Boehm et al. 2009).


  1. Phragmospores 3-septate, 28 μm or less in length →  5
  2. Phragmospores 3-septate, longer than 28 μm →  6


  1. Phragmospores (12-)14-21(-28) x (3-)4-8(-10) μm, firmly 3-septate, no septal constrictions; end-cells obtuse; cosmopolitan →  Hysterium angustatum Pers.
  2. Phragmospores (14-)15-18(-20) x 5-7 μm; 3- (rarely 2- or 4)-septate; prominently constricted at first-formed septum; basal cell extended; red hamathecial pigment; neotropical →  Hysterium asymmetricumCheca, Shoemaker & Umaña


  1. Phragmospores fusoid, slightly curved, guttulate; (20-)25-40 x (4-)5-14 μm; West and East Africa, Russian Far East →  Hysterium vermiforme Massee
  2. Phragmospores fusoid, curved, highly guttulate; 40-57 x 11-15 μm; on Pinus, North America, China, Russian Far East →  Hysterium macrosporumPeck


  1. Phragmospores or dictyospores (4-) 6- to 8- (11-) celled, fusiform in outline, with +/- swollen supra-median cell(s) →  8
  2.  Phragmospores with more than 11 septa, fusiform, pale brown, (13-)14-15(-21)-septate, (35-)45-50(-60) x (10-)12-13(-14) μm; Africa → Hysterium velloziae Henn.


  1. Swollen supra-median cell(s) present, either phragmospores or dictyospores (Oedohysterium) →  9
  2. Phragmospores only, no swollen supra-median cells(s) present → 11


  1. Dictyospores lightly pigmented, 22-25(-27) x 5-6 μm, with (5-)6 transverse and 1 vertical septum in either cell or both cells adjacent to the primary septum, absent in some spores, with a swollen supra-median cell; typically with red pigment in the hamathecium; neotropical (Costa Rica) →  Oedohysterium pulchrum (Checa, Shoemaker & Umaña) E.W.A. Boehm & C.L. Schoch
  2. With no red pigment present → 10


  1. Phragmospores with (4-)6-8(-11) septa, slightly curved, fusiform, at first hyaline-yellow then reddish brown at maturity, if 5-septate, showing a swollen cell at the second position, if 6-septate, often the third from the top, +/- median septal constriction, (20-)23-28(-38) x (5-)7-10(-13) μm; cosmopolitan →  Oedohysterium insidens (Schwein.) E.W.A. Boehm & C.L. Schoch
  2. Phragmospores larger, fusiform, straight to curved, at first hyaline, then yellow or pale brown, finally deep brown; swollen supra-median cell(s) present, (3-)5-9(-11) septa, with median septal constriction; (34-)38-50 x 11-15 μm; cosmopolitan →  Oedohysterium sinense(Teng) E.W.A. Boehm & C.L. Schoch


  1. Phragmospores fusiform, narrow, straight to very slightly curved, pale hyaline at first, then pale-yellow at maturity, with highly refractive guttules, in every cell, with (7-)9(-11) septa, no supra-median swollen cell(s), (35-)40-45(-55) x (7-)9-10(-12) μm; North America →  Hysterium barrianumE.W.A. Boehm, A.N. Miller, G.K. Mugambi, S.M. Huhndorf & C.L. Schoch
  2. Phragmospores oblong, wide, slightly curved, bulging on one side, nearly hyaline and 1-septate  at first, becoming clear brown and 7-septate, septa highly asymmetric, (2-)3 of the septa close to each end, the two central cells much larger; 48-67 x 15-20 μm; North America →  Hysterium magnisporumW.R. Gerard

Hysterium pulicare (Lightf. : Fr.) Pers.

Fries, E. 1823. Syst. Myc. II: 579-580.

Hysterium acerinum Westend. (after Bisby)
Hysterium acervulatum Schw. (after Saccardo, 1883)
Hysterium alneum (Ach.) Schroter, 1893 Lichen alneus Ach. (after Fries, 1823)
Hysterium betulignun Schw., 1834
Hysterium biforme Fries, 1823
Sphaeria cistula Wallr. (after Saccardo, 1883)
Osterion europaeum Duby, 1862
Hysterium pedicellatum Schum. (after Fries, 1823)
Hysterographium pulicare Corda, 1842
Hysterium pulicare var. acerinum (West.) Sacc., 1883
Hysterium pulicare var. juglandis Schw. (after Saccardo, 1883)
Hysterium pulicare var. leave Pers. (after Saccardo, 1883)
Hysterium pulicare var. lenticulare Fries, 1823
Hysterium pulicare var. striatum Chev. (after Saccardo, 1883)
Hysterium rosmarini Dias et da Camara, 1952
Hysterium teres Schw., 1834
Hysterium truncatulum Cooke et Peck (in Cooke, 1877)
Lophium unguiculatus Wallr., 1833

Cosmopolitan. On living tree bark or dead wood of Pinus, Larix, Populus, Salix, Juglans, Ostrya, Betula, Alnus, Castanea, Quercus, Ulmus, Platanus, Aesculus, Tilia, Rhododendron, Olea, & Rosmarinus.

Ellis & Everhart (1892): “Hysterothecia scattered or gregarious, superficial, variable in shape, oblong, ellipsoid, longitudinally striate, black, lips obtuse, slightly open exposing the linear disk, about 1mm long & 0.5mm broad. Asci clavate. Ascospores sub-biseriate, oblong, straight or slightly curved, three septate, hardly constricted, the two end cells paler, straight or nearly so, each cell with a single nucleus, 18-25 x 7-9 μm. Common on bark of various deciduous trees. Very variable in the shape of the hysterothecia, which in the typical form are short & broad, sub-elliptical, but elongated oblong forms are not uncommon, though in this respect European spp. show less variation than the American.”

Bisby (1941): “Occurs on bark & wood of broadleaved trees, especially of Betula. Found on rough, black areas on bark of living Betula (Surrey, UK, Jan.). Hysterothecia scattered or gregarious, inconspicuous, superficial or nearly so, 0.4 – 1mm long, 0.3 – 0.4mm wide, dull black, marked with an indistinct line or two each side of & parallel with the central cleft; the cleft gradually widens to expose the hymenium, which is coloured dark brown by the tips of the paraphyses; asci clavate, 8-spored, 1 – 3 seriate, about 100 μm long, spore-bearing part 50 – 80 x 15 – 20 μm; ascospores 21 – 26 x 6 – 8 μm, 3-septate, the two central cells olive-brown & larger than the end cells; both end cells paler in about 80% of the spores, only one end cell paler in about 10% & all four cells brown in 10%.”


Hysterium pulicare (Lightf. : Fr.) Pers. From Zogg (1962), pgs. 22, 24 & 130.

Hysterium angustatum Alb. et Schw.
Alb. et Schw. 1805. Consp. Fung. Lusat.: 55.

Hysterium acuminatum Fries, 1823
Hysterium acuminatum var. alpinum Rehm (after Saccardo, 1883, & Rehm, 1896)
Gloniella ambigua Karst., 1891
Hysterium angustatum var. cerotoniae Toll, 1905
Hysterium eucalypti Phill. et Hark., 1884b
Hysterium karstenii Lohman, 1939
Hysterium lentisci Rolland, 1901
Hysterium pulicare var. angustatum Kunze (after Fries, 1823)
Hysterium pulicare var. totarae Sacc., 1908

Cosmopolitan. On bark & old wood of Podocarpus, Pinus, Larix, Picea, Juniperus, Chamaerops, Populus, Ostrya, Corylus,Betula, Fagus, Quercus, Ficus, Pyrus, Rubus, Rosa, Prunus, Pistacia, Acer, Aesculus, Allophylus, Dodonaea, Cistus, Myrtus, Eucalyptus, Erica, & Rosmarinus.

Ellis & Everhart (1892): “Hysterothecia gregarious or crowded, more or less immersed in the bark or often superficial, mostly elongated or linear, nearly smooth, black, 0.75-1.25mm long, lips more or less open. Asci 75-80 x 12-15 μm. Ascospores sub-biseriate, oblong, obtuse, three-septate, all of the cells brown, usually with a single nucleus per cell, measuring 15-22 x 6-7 μm. On wood & bard of various hardwood trees.”

Lohman (1933): “Hysterothecia (0.6-) 0.8 – 1.2 x 0.4 mm, oblong, rounded above with a prominent fissure, rugose-punctate to faintly longitudinally striate, straight to subflexuous, densely aggregated, most irregularly oriented, & superficial upon a greening black crust dense with algal cells. Asci 105 – 120 x 10 – 16 μm including the stalk; paraphyses filiform, much branched above & forming an epithecium. Ascospores 22 – 26 x 6.5 – 8 (9) μm, biseriate, elliptic fusiform & slightly curved, rich brown & 3-septate with the cells swollen. On bark & wood, living Betula alba var. papyrifera (Marsh.) Spach. (WI, Sept.).”

Lee & Crous (2003): “Ascomata hysterothecioid, subglobose to globose in vertical section, solitary to gregarious, erumpent to superficial with base immersed, straight to flexuous, ellipsoid or elongated with pointed extremes, opening by a depressed longitudinal slit, 0.4 – 0.6mm side, 0.1 – 0.2mm high. Peridium consisting of three layers, up to 25 μm in dia., carbonaceous, outer layer dark, inner layer hyaline, compressed, middle layer consisting of 1 – 2 rows of thick walled, brown cells. Pseudoparaphyses cellular, hyaline, septate, flexuous, branched, 1 – 2 μm wide. Asci bitunicate, cylindric to claviform, stipitate, octosporous, biseriate, 63 – 87 x 8 – 10 μm. Ascospores (14-) 16 (-18) x (4-) 5 (-6) μm, (mean = 16 x 5 μm), ellipsoid, slightly curved, light brown, the end cells are rarely paler than the centre cells, biseriate, with three transverse septa, often slightly constricted at medium septum. Concolorous, with less than 5% of ascospores versicolorous in a given ascoma.”



Hysterium angustatum Alb. & Schw. From Zogg (1962), pgs. 22, 27 & 130.

Hysterium hyalinum Cooke & Peck

Lohman (1934): “Hysterothecia loosely aggregated and forming cinereous patches on the weathered wood, black and carbonaceous, 1.5-2 or as much as 2.5 mm long, 0.25-0.35 mm broad, erumpently superficial with the ends rounded when exposed, minutely rugose-punctate and occasionally faintly longitudinally striate, thick-walled, either the basal or lateral wall measuring up to 85 μm, with the longtitudinal furrow prominent; asci cylindric-clavate, (75-)85-110 x 15 μm, paraphysate with the paraphyses brtanched and interwoven above; ascospores irregularly biseriate, fusiform, hyaline to pale brown, 20-26(-28) x 6-8.5 μm, mostly 3- but occasionally 4- or 5-sepate, constricted at the septa when mature. The ascospores do, however, become pale brown when matured. Pycnidial and conidial (Sporodesmium) stages present”.

Hysterium hyalinum Cooke & Peck. From Lohman 1934.


Hysterium asymmetricum Checa, Shoemaker & Umaña

Checa J, Shoemaker RA, Umaña L. 2007. Mycologia 99: 288.

Checa, Shoemaker & Umaña (2007): “Ascomata semi-immersed, hyteriform, 0.5 – 1.5mm long, 250 – 300 um wide, 250 – 300um high, smooth, glabrous. Sulcus central. Wall in longitudinal section laterally uniformly 40 – 60um thick of 10 – 12 layers of rectangular, brick-like, 12 – 14 x 2 – 3um pseudoparenchyuma cells, compressed near centrum. Paraphyses numerous, 1um wide, aseptate, without guttules, without slime coating, outermost centrum tissue red. Asci bitunicate, numerous, in a basal cluster, cylindrical to slightly clavate, 80 – 90um x 10 – 12um (pars sporif.), later with narrow stalk about 100um long, with eight, overlapping linearly biseriate ascospores to uniseriate near stalk. Ascospores terete, ellipsoidal, L/W 3.2, inequilateral to slightly curved, (14-) 15 – 18 (-20) x 5 – 7um, transversely (2) 3 (4) septate, in sequence 2:1:2(3), without vertical septa, first-formed septum supramedian (0.44), constricted at first-formed septum, without dots at ends of septa, septa thin with central pore, widest at short second cell from apex, basal cell longest, uniformly pale reddish brown, without guttules, smooth, without sheath.” Neotropical: Collected from Guanacaste, Tempisque, National Park Palo Verde, Costa Rica.

 Hysterium asymmetricum Checa, Shoemaker & Umaña. From Checa et al. (2007).


Hysterium vermiforme Massee

Massee. 1901. Kew Bull., Nrn. 175-177: 150-169.

Rare. Africa (Gold Coast). For a long time, only known from original collection (Zogg, 1962). But recently described from the Russian Far East (Vasilyeva 1999) and from East Africa (Kenya) in Boehm et al. 2009b.

Massee (1901): “Perithecia superficialia, gregaria, atra, carbonacea, lineari-elongata seu vermiformia, utrinque acutiuscula, medio rima longitudinali percursa, 2 – 4 mm longa, 0.5 mm lata, transverse striatula. Asci cylindracei apice truncato-rotundati, ocrospori. Sporae 1-seriatae, cylindraceo-ellipsoideae, utrinque obtusiusculae, triseptato-costrictae, brunneae, 35 – 40 x 12 – 14 um. Paraphyses filiformes. Gold Coast, West Africa. On dead branches still covered with bark, Botanic Gardens, Aburi, Johnson, 69. A very fine species, allied to H. eumorphum Sacc.”

Vasilyeva (1999): “Hysterothecia elongated, superficial, straight to subflexuous, black, 0.5 – 1.5 x 0.1 – 0.2 mm. Asci cylindrical,, short-stipitate, 120 – 140 x 20 – 24 μm.. Ascospores biseriate, fusiform, 3-septate, brown, 35 – 40 (46) x 8 – 10 (12) μm. On wood of Salix sp. Distribution in Russian Far East: Amur Region. Ascospore length corresponds also to Hysterium sinense Teng (38 – 50 μm), but the latter species differs in ascospore septation having up to 7 septa & somewhat wider ascospores (11 – 15 μm).”

 Hysterium vermiforme Massee. Fig. 2 Boehm et al. (2009b).


Hysterium barrianum E.W.A. Boehm, A.N. Miller, G.K. Mugambi, S.M. Huhndorf & C.L. Schoch, sp. nov.

MycoBank MB515330. Boehm E.W.A., Mugambi G., Miller AN, Huhndorf SM, Marincowitz S, Spatafora JW & Schoch CL. 2009b. A phylogenetic reappraisal of the HysteriaceaeMytilinidiaceae & Gloniaceae, with keys to world species. Studies in Mycology 64: 57.

Etymology: Named after the late Dr Margaret E. Barr, preeminent American mycologist.

Ascomata inconspicue hysterothecioidea, modice compressa e latere in parte superiore, paulo conniventia, sulco inconspicuo angusto, latera paucis striis profundis praedita; ascomata recta vel flexuosa, sessilia, raro furcata, matura altiora quam lata, 1-2.5 mm longa, 250-450 µm alta, 200-300 µm lata. Pseudoparaphyses hyalinae, cellulares, 1-2 µm latae, supra ascos ramosae epithecium formantes. Asci bitunicati, cylindrici, breviter stipitati, (110-)125-135 x 15-20 µm. Phragmosporae fusiformes, angustae, rectae vel paulo curvatae, primum hyalinae, maturae pallide luteae, quaque cellula guttulis magnis refringentibus repleta, (7-)9(-11)-septatae, (35-)40-45(-55) x (7-)9-10(-12)  μm.

Ascomata atypically hysterithecioid, somewhat laterally compressed in the upper region, slightly connivent, sulcus very shallow, existing as a narrow rim, sides laterally striate, striae few and deep, straight to flexuous, sessile on the substrate, rarely bifurcating, taller than wide at maturity: 1-2.5 mm long x 250-450 μm high, 200-300 μm wide. Pseudoparaphyses hyaline, cellular, 1-2 μm wide, branched above the ascal layer to form an epithecium. Asci bitunicate, cylindrical, short-stipitate, (110-)125-135 x 15-20 μm (n = 9). Phragmospores fusiform, narrow, hyaline and straight when young, becoming pale-yellow to lightly clear-brown, and curved when mature, highly guttulate, with guttulae large, highly refractive, present in every cell, with (7-)9(-11) septa, measuring (35-)40-45(-55) x (7-)9-10(-12) μm when mature (n = 27).

Specimens examinedU.S.A., Tennessee, Sevier Co., Great Smoky Mountains National Park, Elkmont, Little River Trail, 35˚ 39′ 13.4” N, 83˚ 34′ 44.7” W, 686 m elev., 5 Nov. 2007, A.N. Miller, S.M. Huhndorf, J.L. Crane, T.J. Atkinson, I. Promputtha, M. Grief, G.K. Mugambi, & P. Chaudhary, deposited as ILLS 59908 (ANM 1495) = holotype; BPI 879783 = paratype; Tennessee, Sevier Co., Great Smoky Mountains National Park, Chimney Tops Picnic Area, Cove Hardwood Loop Trail, 35˚ 38′ 10.7” N, 83˚ 29′ 32.1” W, 4 Nov. 2007, A.N. Miller, S.M. Huhndorf, J.L. Crane, T.J. Atkinson, I. Promputtha, M. Grief, G.K. Mugambi & P. Chaudhary, deposited as ILLS 59907 (ANM 1442), and BPI 879784.

Notes: A superficial resemblance exists between Hysterium barrianum in Clade C, with H. sinense in Clade D. The phragmospores of H. barrianum (Fig. 2N-Q) have a similar number of septa, (7-)9(-11), as those of H. sinense (Fig. 3H), the latter with (3-)5-9(-11) septa. The two species also have spores of similar length. However, the width measurements of H. barrianum, (35-)40-45(-55) x (7-)9-10(-12) μm, serve to separate it from H. sinense, (34-)38-50 x 11-15 μm. Most importantly, H. barrianum does not possess a swollen or tumid supra-median cell, as does H. sinense and the closely related H. insidens. Furthermore, H. barrianum is highly guttulate, and lightly pigmented at maturity, whereas H. sinense and H. insidens possess few if any guttulae, and are much darker in pigmentation at maturity. Lastly, molecular data place the species in different groups within the Hysteriaceae 

Hysterium barrianum E.W.A. Boehm, A.N. Miller, G.K. Mugambi, S.M. Huhndorf & C.L. Schoch (Boehm et al. 2009b).


Hysterium macrosporum W.R. Gerard

Gerard In Peck. 1874. 26th Rep. State Mus. N.Y. for 1872: 35 – 91.

Rare. Known originally only from original collection. Collected from dead wood of Pinus from New York, authenticated by Bisby (1932). Also descirbed from China (Teng 1933), and the Russian Far East (Vasilyeva 1999).

Ellis & Everhart (1892): “Hysterothecia superficial or nearly so, oblong or elliptical, sometimes slightly flexuous 200-400 μm long, black, opening by a narrow chink, the lips slightly striate. Asci sub-cylindrical, 125-150 x 25-30 μm, four- to eight-spored. Ascospores crowded in the ascus, oblong or sub-fusiform, sometimes slightly curved, at first colorless & uni-septate, then colored & tri-septate, 40-57 x 12-15 μm. On decaying wood of Pinus, New York (Peck).”

Teng (1933): “Hysterothecia scattered to gregarious, 0.5-1.7 x 0.25-0.3mm, more or less parallel, straight or slightly flexuous, faintly striate; asci clavate, short-stipitate, 120-160 x 22-30μm; spores multiseriate, oblong-fusoid, three-septate, straight or slightly curved, 48-64 x 11-15μm. On decorticated wood of conifers. Kiangsu: I-hsin, Deng 256. Fukien: Kushan, Teng 1912”.

Vasilyeva (1999): “Hysterothecia scattered or in small groups, elongated, superficial or slightly immersed, straight to subflexuous, black, ca. 3mm long & 0.2mm wide. Asci cylindrical shrot-stipitate, 140 – 160 x 26 – 29 μm. Ascospores 2 – 3 seriate, fusiform, 3-septate, brown, 60 – 66 x 10 – 12 μm. On wood of Pinus koraiensis Seibold et Zucc. Primorsky & Khabarovsk Territories, Russian Far East. This species is restricted to Pinus wood. It was described from NY in USA & is know also from China (Teng, 1933). Such distribution suggests the association with fragments of ancient Tertiary floras conserved in the Eastern USA & Eastern Asia.” Note: Vasilyeva lists this as: Hysterium macrosporum Peck (not Gerard).

Hysterium macrosporum W.R. Gerard. From Teng (1933).


Hysterium magnisporum W.R. Gerard
Gerard. 1873. Bull. Torr. Bot. Cl. 4: 64.

Very rare. Known only from original collections. Collected from old Carya & Quercus wood.

Ellis & Everhart (1892): “Hysterothecia erumpent-superficial, about 1mm long, straight or slightly curved, ends sub-obtuse, black, sub-shining, longitudinally striate; lips slightly open so as to leave but a narrow fissure; usually one or two of the striae on each side, near the apex are deeper & more distinct. Asci clavate 150 x 35-40 μm, with a short stype & with abundant paraphyses. Ascospores irregularly crowded, broad, fusoid-oblong, slightly curved or a little bulging on one side, nearly hyaline & uni-septate at first, becoming deep clear brown & seven septate, three of the septa close to each end, measuring 50-60 x 15-20 μm. On a dead hickory limb, Poughkeepsie, NY (Gerard) & on dry decaying oak wood Newfield, NJ (Ellis).”

Hysterium magnisporum W.R. Gerard. From Teng (1933).


Hysterium velloziae P. Henn.

  1. Henn. Hedwigia 1908, 47, 266-270.

Collected from Vellozia (Velloziaceae). Doubtfully included as a Hysterium according to Zogg (1962). However, recently reported from South Africa (van der Linde, 1992).

van der Linde (1992): “Zogg (1962) retained this species until more information on it was available. He suggested that this species had not been collected again since it was originally collected & described. Fruitbodies arranged in evenly distributed groups, embedded or erumpent, broad-ellipsoid with almost abrupt ends, slit broad, straight, not branched, up to 1.2 x 0.5 mm. Pseudoparaphyses hyaline, septate, filiform, not thickened much at the tips, branched to from an epithecium. Asci irregularly biseriate, broad-cylindrical, 8-spored, 130 – 140 x 20 – 25 μm. Ascospores light brown with dark brown septa, fusiform, phragmosporous,, 13 – 21 septate, most commonly 14- or 15-septate, 45 – 50 (-60) x 10 – 12 (-14) μm.”

Hysterium velloziae P. Henn. From van der Linde (1992).