Colonies thin, brown to black, effuse. Mycelium immersed, composed of branched, septate, pale brown to brown hyphae 2.5-6.5 µm wide. Conidiophores erect, arising singly or in groups of up to 4 from the larger immersed hyphae, simple or once-branched at the base, straight or flexuous, subcylindrical, brown to dark brown below, very pale brown to subhyaline above, up to 165 µm long, 4.8-7 µm wide just above the base which may be swollen up to 9 µm, up to 15-septate, tapering slightly toward the bluntly rounded apex which is 4.5-5.4 µm wide. The lower cells of the conidiophore are 20-27 µm long but the cells are progressively shorter toward the apex where they may be as short as 5.5 µm. Up to 11 of the distal cells (except the apical cell) of the conidiophore bear a solitary conidium or the scar of a seceded conidium: the scar is on a cylindrical denticle, up to 1.8 µm long and 1.5 µm wide, borne laterally below the distal septum of the cell. Conidia are solitary, blastic and lateral on a denticle on successive penultimate cells of the conidiophore: they are obovoid, sometimes slightly denticulate at the basal scar, smooth, 2-septate, the 2 lower cells being brown and the distal cell paler, with a dark band of wall overlying each septum. A small, thin area of wall (? germ pore) is found to one side of the basal scar and apically on the terminal cell, and occasionally on the central cell. Conidia measure 13.5-16.2 x 7.2-9.0 µm.

Coloniae sparsae, effusae, brunneae vel atrae.Mycelium immersum, ex hyphis septatis, ramosis, pallide brunneis 2.5-6.5 µm crassis compositum.Conidiophora singulariter nata vel ad 4 aggregata, erecta, simplicia vel ad basim furcata, recta vel flexuosa, subcylindrica, ad 15-septata; basim versus cellulae 20-27 µm longae, apicem versus gradatim breviores (ad 5.5 µm longae). Conidiophora ad 165 µm longa, ad basim inflata (ad 9 µm), supra basim 4.8-7 µm crassa, apicem versus 4.5-5.4 µm crassa, apice obtusa. Cellulae 1-11 distales (extra cellulam apicalem) conidiiferae.

Conidia blastica in denticulis solitariis lateraliter in cellulis penultimis successivis oriunda, obovoidea, inter¬dum ad basim parce denticulata, laevia, 2-septata, cellulis binis inferioribus brunneis, cellula apicalis pallidiore, taenia atrobrunnea vel atra ad septa. Cellulae polares (interdumque medialis) poris germinationibus praeditae. Conidia 13.5-16.2 x 7.2-9 µm.

Holotypus in ligno putrido Freycinetiae banksii, Nova Zelandia, "Auckland Province, Cornwallis", 31. XII. 1962, J. M. Dingley, PDD 36099 (DAOM 93822).

Colonies effuse, punctate with shining black sporodochia. Mycelium immersed or partly immersed, com¬posed of branched, septate, subhyaline to pale brown hyphae 2.5-11 µm wide. Sporodochia scattered or crowded, elliptical to rounded, pustulate or flattened, as small as 100 µm or up to 1 mm long, composed of a base of densely aggregated hyphae bearing crowded conidiophores which are centrally erect and marginally diverging. Conidiophores simple, straight or slightly curved, with a thin outer gelatinous layer, composed of a sessile or stalked conidiogenous cell; when present the stalks are up to 20 µm long, subhyaline to pale brown, cylindrical and 4.5-5.4 µm wide. Conidiogenous cells brown, 6-14.5 µm long, 4-5.4 µm wide below, expanding to 5.6-8 µm at the distal end which may be flattened or slightly convex after conidium secession. Percurrent proliferations are narrowed as they extend through the half-septum retained by the conidiogenous cell after conidium secession and then expand into a shortly-stalked conidiogenous cell: one to three such percurrent pro-liferations have been seen on conidiophores.

Conidia are solitary, blastic and terminal on the conidiogenous cells and their successive proliferations. They are obovoid, brown, slightly paler at the ends, mostly 5-septate with the two central cells much larger than the paired end cells: conidia are flattened at the basal scar, which is 6.3-8 µm wide, and they are at first rounded at the apex. They measure 50-65 x 23.5-30.5 µm. Occasional conidia are 4-septate with an inordinately large, single central cell with two small cells at each end, or they may be 6-septate with an extra, small cell at base or apex. Occasionally, three central cells maybe larger than the others. Seven-septate conidia are rare. Whilst still attached to their individual conidiogenous cells conidia usually produce up to 9 small and more or less globose conidia of a synanamorph from the distal cell of the conidium: these are sessile or borne on a short, simple or branched stalk. They are pale brown to brown, 9-12.5 µm wide with a configuration of cells reminiscent of textura epidermoidea. The thin gelatinous layer which surrounds the conidiophore also extends over the conidia and their apical synanamorph.

On rotten wood, Auckland Province, (1) Nothofagus menziesii, Mangorewa Gorge, 20. III. 1963, S.J. H., DAOM 167421; (2) unidentified host, Centennial Track, Upper Piha valley, Waitakere Range, 2.V.1963, S.J.H., PDD 20961 (type) (DAOM 93817).

Coloniae effusae cum sporodochiis atris punctatae. Mycelium immersum vel partim superficiale, ex hyphis ramosis, septatis, subhyalinis vel pallide brunneis 2.5-11 µm crassis compositum.Sporodochia dispersa vel aggregata, elliptica vel rotundata, pustulata vel depressa, ca 100 µm diam. vel ad 1 mm longa.Conidiophora simplicia, brevia, recta vel parum curvata, dense aggregata, ex cellulis conidiogenis smgulis breviter stipitatis vel ex cellulis conidiogenis sessilibus composita. Stipes ad 20 x 4.5-5.4 µm, subhyalinus vel pallide brunneus cylindricus. Cellula conidiogena brunnea 6-14.5 µm longa, basi 4-5.4 µm crassa, ad apicem 5.6-8 µm crassa. Dein conidiophora (cellulae conidio¬genae) proliferunt per proliferationes conidiogenas ad 3 percurrentes.

Conidia solitaria, blastica, primo in apice cellulae conidiogenae et dein proliferationis cujusque successive oriunda, obovoidea, brunnea, ambitu pallidiora, plerumque 5-septata, cellulis binis centralibus majoribus alias biros apicalibus basalibusque parvioribus, 50-65 µm longa, 23.5-30.5 µm crassa. Conidia et conidiophora circumdata sunt tumca gelatinosa tenue.Conidia secondaria 1-9 sessilia vel breviter stipitata super cellulam apicalem oriunda, subglobosa, pallide brunnea vel brunnea 9-12.5 µm diam. Paries aliter dictu "textura epidermoidea".

Holotypus in ligno putrido, Nova Zelandia, "Auckland Province, Centennial Track, Upper Piha Valley, Wai¬takere Range", 2.V.1963, S. J. Hughes, PDD 20961 (DAOM 93817).

The conidia of Hadrosporium dingleyae are smaller than those of the type species, have fewer septa, and they bear a synanamorph at the distal end. Hughes (1979) indicated that the conidia of the synanamorph produced by the new species are similar to those produced by species of Xenosporium Penzig et Saccardo (Hughes 1978). The production of nested proliferations by species of Hadrosporium is paralleled in Phragmospathula Subramanian et Nair (Hughes 1979) but there are apparent differences in the origin of these proliferations. A better understanding of these genera would certainly result from a closer investigation, especially at the ultrastructural level. Many proliferations in Hadrosporium dingleyae seem to have arisen within the conidiogenous cell itself. In others the proliferations appear to have arisen by an extension of the lower septum of the conidiogenous cell or from an extension of penultimate cell through that septum.

Colonies black, effuse, hairy. Mycelium immersed, composed of branched, septate, pale brown to dark brown hyphae 3.5-9 µm wide, forming immersed or partially immersed subglobose to flattened stromata up to 100 µm wide, but larger by confluence, composed of brown to dark brown cells up to 16 µm wide.
Conidiophores scattered or crowded, arising singly from small aggregations of a few cells or in groups of two or more from the stromata; they are simple, flexuous, subcylindrical, dark brown to black below, pale brown to dark brown toward the apex, thick-walled (up to 3 µm), smooth or distally roughened, septate at 40-63 µm intervals for most of their length with the cells-more or less progressively shorter toward the apex where they are mostly 14¬-30 µm long. Conidiophores are up to 2 mm long, 18-23 µm wide just above the swollen base and 15-21 µm wide toward the apex; pores in the conidiophores indicate the position at which the solitary conidia developed.

The distal cell of the condiophore bears a con¬spicuous terminal "pore" and usually 1 or 2 sub-apical pores; one or sometimes two similar pores are found in 1-6 other cells toward the apex of the con¬idiophore. Pores are 1.8-2.5 µm wide. Conidia obclavate, often conspicuously rostrate, smooth toward the base and apex, elsewhere with the exospore reticulate-foveate to irregularly so, golden brown to brown, paler toward the apex and dark brown or occasionally black around the immediate base which may be slightly denticulate. The lateral wall is 7-9 µm thick below but thinner toward the apex; usually the conidia have 3 or 4, thick (up to 5.5 µm), main transverse septa, each often with a thin central darker lamella. Below the lower two or three main septa thin-walled trans¬verse septa are formed so that conidia are finally 14-to 18-septate; 4-14 scattered, thin-walled, longitudinal or oblique septa arise so that mature conidia are essentially dictyoseptate. Conidia measure 92-145 x 29-38 µm with the rostrum c. 5.5 µm wide and 15-115 µm long; the rostrum may extend into simple or once branched pale brown germ tube with cells up to 100 µm long.

On dead twigs.

Coloniae effusae, atrae, pilosae. Mycelium immersum, ex hyphis septatis, ramosis, pallide brunneis vel atrobrunneis 3.5-9 µm crassis compositum. Stromata immersa vel partim superficialia, subglobosa vel depressa, usque ad 100 µm lata, ex cellulis brunneis vel atrobrunneis ad 16 µm latis composita.
Conidiophora oriunda sive pluraliter ex stromata sive singula ex cellulis perpaucis aggregatis, simplicia, flexuosa, subcylindrica, septata (cellulis plerumque 40-63 µm longis sed apicem versus cellulis 14-30 µm longis), basim versus atrobrunnea vel atra laeviaque, apicem versus pallidiora, crasso-tunicata (ad 3 µm) interdum asperata, usque ad 2 mm longa, supra basim 18-23 µm crassa, apicem versus 15-21 µm crassa, cellula terminali poris 1-3 in apice conidiiferis praedita, cellulis subterminalibus 1-5 etiam poris 1 vel 2 lateralibus conidiiferis praeditis. Conidia ad poros conidiophori oriunda, obclavata saepe rostrata, basim et apicem versus laevia, ceteris inconspicue subreticulate-foveata, aureo-brunnea vel brunnea, apicem versus pallidiore, ad basim interdum denticulata et atrobrunnea vel atra, lateraliter crasso-tuni¬cata (ad 9 µm), ad maturitatem dictyoseptata, septis 14-18 transversalibus, septis 4-14 longitudinalibus vel obliquis, dispersis. Conidia 92-145 x 29-38 µm, rostro ca 5.5 µm crasso,15-45 µm longo, germinante elongascente.

Holotypus in ramulis emortuis, Nova Zelandia, "Auckland Province, Walker's Bush, Henderson Valley, Waitakere Range", 30.I.1963, F. J. Morton, PDD 20506 (DAOM 109608).

(1) Disoxylon spectabile, North Auckland, Puketi Forest, 20. VI. 1963, J. M. Dingley, DAOM 93751; (2,3) Vitex lucens, Auckland Province, Piha, Waitakere Range; (2) 31.I.1963, S.J.H., DAOM 143999; (3) 31.VII.1963, J.M.D., PDD 36098 (type) (DAOM 109629); (4) unidentified branch, Auckland Province, Cornwallis, 3.I. 1963, S.J.H., DAOM 143998.

Colonies effuse, black, hairy. Mycelium immersed, composed of branched, septate, pale brown hyphae 3.5-9 µm wide. Conidiophores scattered or crowded, arising singly or sometimes in pairs or threes, mostly simple, straight or flexuous, subcylindrical, dark brown to black below, paler above, thick-walled (up to 2.7 µm), septate at 12-45 µm intervals, 165-330 µm long, 12.5-14.5 µm wide just above the base which is swollen and 18-21.5 µm wide, 10-11 µm wide just below the apical cell which is slightly swollen and 11.5-13.5 µm wide. After conidium secession the apical cell bears a conspicuous terminal "pore" and occasionally a second subapical or lateral pore; one or two similar pores are found in 1-3(-4) other distal cells of the conidio phore. Pores are 1.3-1.8 µm wide and indicate the positions at which solitary conidia developed.

Conidia obclavate to fusiform, sometimes shortly rostrate, smooth, golden brown to dark brown, paler toward the apex, (5-)6-7(-8)-septate, 56-63 x 20-21.5 µm (5-septate), 63-81 x 16-21 µm (6-septate), 74-90 x 18-23.5 µm (7-septate), 88-103 x 19-21 µm (8-septate). Terminal conidia are straight but attached lateral ones are seen to be upwardly curved.

Coloniae effusae, atrae. Mycelium immersum, ex hyphis septatis, ramosis, pallide brunneis 3.5-9 µm crassis compositum. Conidiophora plerumque singulariter nata, erecta, plerumque simplicia, recta vel flexuosa, subcylindrica, septata (cellulis 12-45 µm longis), basim versus. atro¬brunnea vel atra, apicem versus pallidiora, crasso-tunicata (ad 2.7µm), 165-300 µm longa, ad basim inflata (18-21.5 µm), supra basim 12.5-14.5 µm crassa, apicem versus 10-11 µm crassa, cellula terminali parce inflata (11.5-13.5 µm) poris 1 vel 2 in apice conidiiferis praedita, cellulis subterminalibus 1-3(-4) etiam poris 1 vel 2 laterali¬bus conidiiferis praeditis. Conidia ad poros conidiophori oriunda, obclavata vel fusiformia, interdum breviter rostrata, laevia, brunnea vel atrobrunnea, (5-)6-7(-8)-septata, 56-63 x 20-21.5 µm (5¬-septata), 63-51 x 16-21 µm (6-septata), 74-90 x 18-23.5 µm (7-septata), 88-103 x 19-21 µm (8-septata). Conidia apicalia recta sed lateralia curvata.

Holotypus in ligno putrido Viticis lucentis, Nova Zelandia, "Auckland Province, Piha, Waitakere Range", 31. VII. 1963, J. M. Dingley, PDD 36098 (DAOM 109629).

Broken or damaged conidiophores may regenerate percurrently and reach a length of 450 µm or they may produce one or two lateral branches which are conidiogenous. The presence of occasional lateral branches in some of the collections suggests, at first sight, a Dendryphiopsis but such branching is sporadic and the result of regeneration after damage. The apex of conidia frequently gives the appearance of having gelatinised and this may be accompanied by the formation of a new wall below the old apex.

Helminthosporium novae-zelandiae may be distinguished from other species of the genus by its relatively short conidiophores and by the conidia which are predominantly 6- or 7-septate, broad in relation to their length, and finally dark brown.