Ascomata subcuticular. In vertical section upper wall of unopened ascomata up to 50-60 µm thick. Inner and outer parts of the wall comprise dense, black tissue with no obvious cellular structure, otherwise mostly of dark brown, angular cells. Along the future line of opening, in the inner part of the wall, is a group of thinner-walled, paler cells. In opened ascomata the upper wall is 50-70 µm thick near the opening slit, becoming abruptly thinner about half way to the base of the wall, comprising mostly brown to pale brown, thick-walled, angular cells, but with a patch of dense, black tissue on the inner edge of the wall near the ascomatal opening, and along outermost 5-10 lam of the wall. Exposed face of the broken upper wall is lined with a compact layer of cylindric, hyaline, thin-walled cells. Lower wall 5 µm thick, of 1-2 layers of brown to pale brown, angular cells.

Paraphyses 1.0-1.5 µm diam., circinate at apices, extending 10-15 µm beyond asci. Asci 120-160 x 11-14 µm, clavate-stipitate, tapering to small, truncate apex, sometimes with tiny apical pore, 8spored, spores confined to upper half of ascus. Ascospores 35-45 x 3-4 µm (average 41.2 x 3.1 µm), in face view cylindrical-bifusiform, rounded at apex, tapering near base, 1-1.5 µm wide at central constriction, 0-septate, surrounded by gelatinous sheath.

Conidiomata subcuticular. In vertical section lenticular in shape, upper wall 5 µm thick, of brown material with no visible cellular structure. Lower wall of 2-3 layers of brown to dark brown, thick-walled, angular cells. Lower wall is lined with hyaline, thin-walled cells, on which the conidiogenous cells are held. Conidiogenous cells 7-20 x 2-3 µm, flask-shaped, with a broad base and narrow apex, sympodial proliferation, often with more than one conidium held at apex. Conidia 3-4 x 1 µm, cylindric, straight, 0-septate, hyaline.

ETYMOLOGY: albo = white, rubrum = red; refers to the white or bright red zone of cells lining the ascomatal opening.

H. alborubrum can be difficult to distinguish from two other species often found on the same leaves, H. campanulatum and H. carinatum. The most distinctive macroscopic feature of H. alborubrum is the zone of bright, white or red cells lining the opening slit. Microscopically this species has distinctly bifusiform ascospores, while the other two species have ascospores which are only slightly, if at all, constricted. The anamorph of H. alborubrum also differs in having conidiogenous cells which proliferate sympodially rather than percurrently, and in lacking any wall thickening at the conidiogenous locus.

See also notes under H. carinatum and H. campanulatum.

Ascomata subcuticular. In vertical section the upper wall of unopened ascomata is up to 70 µm thick, comprising mostly brown to dark brown, thick-walled, angular cells. The outer part of the upper wall near the centre of the ascomata is composed of dense, black tissue with no obvious cellular structure, and the dense, black material often extends into what appear to be cracks in the host cuticle. The inside of this part of the upper wall is lined with a layer of hyaline, somewhat disorganised tissue. A narrow extension to this hyaline layer extends vertically through part of the dense, black layer in the outer part of the wall. In opened ascomata the upper wall is up to 85 µm thick near the ascomatal opening, becoming abruptly thinner, to 10-25 µm thick in lower half. Wall comprising brown to dark brown, thick-walled 5-7 µm diam. cells, with dense, black tissue with no obvious cellular structure in the outer part of the wall, near opening slit. Exposed face of the broken upper wall is lined with a layer of 1-4 µm diam., branching, hyaline, thin-walled, cylindric cells. Lower wall 20-40 µm thick, of angular cells, cells dark brown and thick-walled in outer part of wall, paler and thinner-walled in inner part.

Paraphyses 0.8-1.0 µm diam., apices undifferentiated or loosely circinate, extending 20-30 µm beyond asci. Asci 140-160 x 12-17 µm, clavate-stipitate, tapering to small, truncate apex, wall thinner at apex, 8-spored, spores confined to upper half of ascus. Ascospores 21-36 x 4.5-5.5 µm (average 24.8 x 4.8 µm), in face view oblong-elliptic, tapering slightly to rounded ends, 0-septate, surrounded by narrow, gelatinous sheath. Conidiomata subcuticular. In vertical section the upper wall is absent. The lower wall is 5-10 µm thick, of 1-2 rows of thick-walled, brown, angular to cylindric cells. Conidiogenous cells solitary or on short conidiophores, developing on the lower wall, 10-18 x 2-3 µm, cylindric, with percurrent proliferation, sometimes with several distinct annelations near apex. Conidia 5-10 x 1 µm, cylindric, straight, ends rounded, 0-septate, hyaline.

ETYMOLOGY: named after host substrate.

Hypoderma bidwillii can be distinguished by macroscopic appearance. The immature ascomata have a distinctive paler zone along the future line of opening, with this paler zone interrupted near the centre of the ascomata by a small, circular patch of dark tissue. In addition, the distribution of dense, black tissue in the ascomatal upper wall differs from that seen in all other New Zealand Hypoderma spp.

Ascomata subcuticular. In vertical section upper wall of unopened ascomata up to 30-40 µm wide, narrower toward edges, comprising mostly brown to dark brown, thick-walled cells, darker and thicker-walled along the outside of the wall. In unopened ascomata there is a group of thinner-walled, paler cells in the inner half of the wall along the future line of opening. Inside edge of the wall is lined with a one cell wide layer of hyaline, thin-walled, cylindric to globose cells. In opened ascomata the upper wall is up to 40-80 µm thick near the ascomatal opening, becoming gradually narrower toward the base of the wall, comprising dark brown, thick-walled, angular cells, or becoming very dark, with cellular structure . cured. Exposed face of the broken upper wall is lined with a layer of cylindric, thin-walled, hyaline, 15-20 x 3-5 µm cells. Lower wall 10-15 µm thick, of 2-4 layers of brown, thick-walled, angular to cylindric, 4-10 µm diam. cells.

Paraphyses 1-2 µm diam., undifferentiated or irregularly circinate at apex, embedded in persistent gel, extending 15-20 µm beyond asci. Asci 80-130 x 11-16 µm, clavate, tapering to broad, truncate to slightly rounded apex, indistinct central apical pore, 8-spored, spores extending to base of ascus. ascospores 13-19 x 4.5-6.5 µm (average 15.1 x 5.2 µm), in face view elliptic, uniform in shape to both ends, 0-septate, surrounded by a thick gelatinous sheath.

Conidiomata subcuticular. In vertical section the upper wall is less than 5 µm thick, of dense, dark brown material with no obvious cellular structure. Lower wall 3-5 µm thick, of 1-2 layers of brown, thick-walled, angular to cylindric cells. Lower wall is lined with 1-2 layers of hyaline, thin-walled, cylindric cells on which the conidiogenous layer develops. Conidiogenous cells 7-10 x 2-2.5 µm, more or less flask-shaped, tapering to apex proliferation sympodial, often with two conidia held at apex. Conidia 4-5 x 1 µm, cylindric, straight, ends rounded, 0-septate, hyaline.

CHARACTERISUCS IN CULTURE: Ascospores of PDD 45036 germinated on agar plates after 48 hours. Colonies on OA over 85 mm diam. after 6 weeks, aerial mycelium sparse, cottony, white, agar surface becoming dark brown. Black, globose conidiomata forming near edge of the colony, breaking open to expose the conidial ooze. Conidiogenous cells 7-17 x 2-6 µm, with swollen base with more or less cylindric upper part, sympodial proliferation, often with more than one conidium held at apex. Conidia 4.5-8 x 1-1.5 µm, cylindric, ends rounded, straight, 0-septate, hyaline.

ETYMOLOGY: bihospitum = of two hosts; refers to unusual host distribution of this species.

NOTES: H. bihospitum can be distinguished from other New Zealand Hypoderma species by ascospore size and shape, and by ascus shape. Hypoderma species typically have clavate-stipitate asci with an elongate, stalk-like base, with the ascospores confined to the upper part of the ascus. Apart from ascus shape, all other characteristics of the hymenium, and of ascomatal structure and pattern of ascomatal development, conform to the concept of Hypoderma accepted in this study.

The host distribution of H. bihospitum is difficult to explain. When viewed in vertical section the collections on Uncinia tend to have darker upper walls to the ascomata, and, in unopened ascomata, a less well-developed paler zone along the future line of opening. The stippled appearance of the host tissue surrounding the ascomata in the collections on Uncinia is due to the stomatal cavities near the ascomata becoming packed full of dark fungal tissue, and is a feature not found on the collections from Anisotome. Apart from these three somewhat variable features, the collections on the different hosts are indistinguishable both macro- and micromorphologically.

H. bihospitum is the only species of Rhytismataceae found on Anisotome, but both Lophodermium unciniae Johnston and L. breve (Berkeley) de Notaris are also commonly found on Uncinia (Johnston 1989).

Ascomata subcuticular. In vertical section, upper wall of the unopened ascomata up to 60-70 µm thick, comprising mostly brown to dark brown, angular cells, with darker areas along the outer and inside edges of wall, but with a line of paler, thin-walled cells at the centre of the ascomata, along the future line of opening. In opened ascomata the upper wall is up to 90-1 1 0 µm thick near the ascomatal opening, becoming abruptly thinner about half way to the edge of the ascomata. Upper wall comprising either all dense, black tissue with no visible cellular structure, or with a few thick-walled, dark brown, angular cells visible in the centre of the labia. Exposed face of the broken upper wall lined with hyaline to pale brown, thin-walled, cylindric cells. Lower wall 3-5 µm thick, of 1-2 layers of thick-walled, pale brown, angular, 3-5 µm diam. cells. Both walls extending over 200 µm beyond edge of hymenium.

Paraphyses 1-1.5 µm diam., circinate at apices, extending 5-10 µm beyond asci. Asci 110-175 x 11-14 µm, clavate-stipitate, tapering to small, truncate apex, wall undifferentiated at apex, 8-spored, spores confined to upper half of ascus. Ascospores 28-45 x 2.5-3.5 µm (average 37.2 x 2.9 µm), in face view cylindric, apex rounded, near the base tapering to more or less acute base, 0-septate, surrounded by gelatinous sheath.

Conidiomata subcuticular. In vertical section lenticular in shape, upper wall 5 µm thick, of brown to black material with no visible cellular structure. Lower wall of 2-3 layers of brown to dark brown, thick-walled, angular cells. Lower wall is lined with 1-2 layers of thin-walled, hyaline cells on which the conidiogenous cells develop. Conidiogenous cells 6-9 x 2.0-2.5 µm, cylindric, percurrent proliferation, wall thickened at single apical conidiogenous locus. Conidia 3-4 x 1 µm, cylindric, straight, 0-septate, hyaline.

ETYMOLOGY: campanulatus = bell-shaped; refers to ascomatal shape, with a distinctive, flattened, shelf-like plate of tissue surrounding the central, raised part of the ascomata.

NOTES: H. campanulatum is often found in association with two other species, H. carinatum and H. alborubrum. The most distinctive feature of H. campanulatum is the paler, grey, flattened, shelf-like margin to the ascomata.

See also notes under H. carinatum and H. alborubrum.

Ascomata subcuticular. In vertical section the upper wall of unopened ascomata up to 30-40 µm thick, narrower toward edges and at the centre of the ascomata. Upper wall comprising mostly dense, black tissue with no obvious cellular structure, except for the inner part of the wall along the future line of opening, where it comprises thin-walled, hyaline cells. In opened ascomata the upper wall is up to 60-80 µm thick, becoming gradually thinner toward the base of the wall, and toward the ascomatal opening. A few poorly developed, hyaline, cylindric cells initially line the exposed face of the broken upper wall, but these cells are not persistent. Lower wall 5-10 µm thick, of 1-2 layers of brown to pale brown, angular to cylindric cells. Upper and lower walls extending up to 300-400 µm beyond hymenium.

Paraphyses 1.0-3.5 µm diam., undifferentiated or slightly and irregularly swollen near apices, extending 5-10 µm beyond asci. Asci 110-180 x 10-12 lam, clavate-stipitate, tapering gradually to small, truncate apex, wall undifferentiated at apex, 8-spored, spores restricted to upper half of ascus. Ascospores 32-45 x 2.5-4.5 µm (average 37.9 x 3.0 µm), in face view cylindric, tapering slightly to base, with slight or sometimes well-developed constriction near centre of spore, 0-1-septate, surrounded by gelatinous sheath. In many asci ascoconidia are produced from both ends of unreleased ascospores. Asci often becoming packed with the 2.5-6.0 x 1 µm, cylindric, hyaline, 0septate ascoconidia.

Conidiomata subcuticular. In vertical section lenticular in shape, upper wall 5 µm thick, comprising dense, brown tissue with no visible cellular structure. Lower wall of 1-2 layers of cylindric to angular, brown to dark brown, thick-walled cells. Lower wall lined with 1-2 layers of thin-walled, hyaline cells on which the conidiogenous cells develop. Conidiogenous cells 6-11 x 1.5-2.5 µm, cylindric, percurrent proliferation, wall thickened, and sometimes flaring, at the single, apical conidiogenous locus. Conidia 3.0-5.0 x 1.0-1.5 µm, cylindric, straight, ends rounded, 0-septate, hyaline.

CHARACTERISTICS IN CULTURE: Ascospores from PDD 46709 germinated within 24 hours on agar plates. Ascoconidia did not germinate. Cultures on OA 60 mm diam. after 8 weeks, aerial mycelium white, coarse, cottony, tufted, agar surface grey-green to olivaceous with black patches. Scattered, globose, black-walled conidiomata, conidiogenous cells as described from host material, conidia longer, 5-7 x 1-1.5 µm.

ETYMOLOGY: carinatum = keeled; refers to ascomatal shape, with keel-like ridge along opening slit.

NOTES: H. carinatum is easily confused with two other species with similarly sized asci and ascospores, H. campanulatum and H. alborubrum. H. carinatum can be distinguished by its very broad ascomata, greater than I mm wide, and by the keel-like ridge along the ascomatal opening.

The appearance in vertical section of the upper wall of unopened ascomata of H. carinatum is similar to that of H. cookianum. Both species have an ascomatal upper wall thinner along the future line of opening, and with no persistent layer of differentiated cells along the edge of the ascomatal opening. As in other Hypoderma species the ascomata are subcuticular, and the inner part of the upper wall along the future line of opening comprises cells thinner-walled and paler than those of the rest of the wall, the paraphyses are undifferentiated at the apex, and the asci are clavate-stipitate.

See also notes under H. campanulatum, H. alborubrum.

Ascomata subcuticular. In vertical section upper wall of unopened ascomata up to 45-60 µm thick, narrower toward the outside edge and near the centre of the ascomata. Upper wall comprising mostly dense, black tissue with no obvious cellular structure, but with brown to pale brown, angular cells at the narrow, central part of wall. The inside of this central part of the wall is lined with a few thin-walled, hyaline cells. In opened ascomata the upper wall is up to 60-90 µm thick, slightly thinner toward the ascomatal opening and toward the edge of the ascomata. There is no well-differentiated, persistent zone of paler cells lining the exposed face of the broken upper wall. Lower wall 30-45 µm thick, of 5-10 rows of angular cells, brown to dark brown and thick-walled toward the outside of the wall, hyaline and thin-walled toward the inside.

Paraphyses 1.5-2.0 µm diam., undifferentiated at the apex, barely extending beyond asci. Asci 130-175 x 11-13 µm, clavate, becoming clavate-stipitate immediately prior to spore release tapering slightly to the broadly truncate to somewhat rounded apex, wall often with a small pore at the apex, 8spored. Ascospores bifusiform, 22-33 x 3.5-5.0 µm (average 24.5 x 4.1 µm), broadly rounded apex, tapering toward base, constricted to 1.0-1.5 µm diam. near middle of the spore, surrounded by a narrow gelatinous sheath.

Conidiomata subcuticular. In vertical section the upper wall is 3-5 µm thick, comprising brown to pale brown material with no obvious cellular structure. Lower wall 5-10 µm thick, comprising 2-3 rows of angular cells, outer layers of cells brown, inner layers hyaline. Conidiogenous cells develop on the innermost cells of lower wall, 8-15 x 2-3 µm, cylindric, solitary, proliferating sympodially, often with two developing conidia at apex. Conidia 4-6 x I µm, cylindric, ends rounded, straight, 0-septate, hyaline.

ETYMOLOGY: named after host substrate.

NOTES: Ascomatal shape and ascospore shape distinguish this species from H. cordylines, also found on Phormium in New Zealand.

See also notes under H. carinatum.

Ascomata subcuticular. In vertical section the upper wall of unopened ascomata up to 70 µm thick, narrower toward the edges of the ascomata. Wall comprising mostly brown to dark brown, angular cells, but with a group of paler, thinner-walled cells in the inner part of the wall, along the future line of opening. Ascomatal upper wall starts to split open, and a layer of hyaline, cylindric cells begins to develop along the exposed face of the breaking upper wall, before covering host cuticle breaks. In opened ascomata the upper wall is up to 70-120 µm thick near the ascomatal opening, becoming either gradually or more or less abruptly thinner toward the outside edge. Upper wall comprising dark brown, thick-walled, angular, 4-7 µm diam. cells. Exposed face of the broken upper wall is lined with hyaline, thin-walled, 20-30 x 4-5 µm, cylindric cells. Lower wall 10-20 µm thick, of 2-3 rows of brown, thick-walled, angular to cylindric cells.

Paraphyses 1.0-1.5 µm diam., loosely circinate at apex, extending 5-10µm beyond asci. Asci 90-l40 x 11-16 µm, clavate-stipitate, tapering to truncate apex, wall often slightly thickened at apex with inconspicuous central pore, 8-spored, spores confined to upper half of ascus. Ascospores 14-21 x 4.5-6.0 µm (average 17.0 x 5.2 µm), in face view elliptic, tapering more or less equally to both ends, in side view slightly curved, 0-septate, surrounded by gelatinous sheath.

Conidiomata subcuticular. In vertical section upper wall absent. Lower wall of 1-3 layers of brown, thick-walled, angular cells. Lower wall lined with short columns of angular to cylindric, pale brown to hyaline, 4-8 x 4 µm cells, and the conidiogenous cells develop on this layer. Conidiogenous cells 13-22 x 2-3 µm, Solitary, cylindric, tapering to apex, with sympodial proliferation, often with two conidia held at the apex. Conidia 5-9 x 1 µm, cylindric, straight, ends rounded, 0-septate, hyaline.

CHARACTERISTICS IN CULTURE: Ascospores germinating on agar plates within 24 hours. Colonies on OA 60-80 mm diam. after six weeks, aerial mycelium sparse, white, cottony, agar surface pale greyish-brown, with numerous, scattered, black-walled, globose conidiomata. Conidiomata opening by irregular splits in the wall to expose the grey conidial ooze. Conidiogenous cells and conidia the same as described from plant material.

ETYMOLOGY: named after host substrate of holotype.

NOTES: Hypoderma cordylines is macroscopically similar to the common and widespread H. rubi. The two species can be distinguished by ascospore shape, and by the length of the conidia. H. rubi has not been found on Cordyline spp.

Ascomata subcuticular. In vertical section the upper wall of unopened ascomata is up to 50 µm thick, becoming gradually narrower toward the edge of the ascomata, comprising mostly brown to dark brown, angular cells, but along the future line of opening, near the middle of the ascomata, is a wedge-shaped group of paler, thinner-walled cells in the inner part of the wall. The inside edge of the wall is lined with a few hyaline, cylindric to globose cells. In opened ascomata the upper wall is 40-55 µm thick, not varying in width in the top third of the wall, in the lower two-thirds becoming gradually thinner. Wall comprising dark brown, mostly thick-walled, angular, 5-8 µm diam. cells. Exposed face of the broken upper wall is lined with hyaline, thin-walled, 15-20 x 3-4 µm, cylindric cells. Lower wall, 10-1 5 µm thick, of 3-4 layers of dark brown, thick-walled, globose to angular cells.

Paraphyses 1-1.5 µm diam., undifferentiated or loosely circinate at apices, extending 10-15 µm beyond asci. Asci 120-155 x 8-12 µm, clavate-stipitate, tapering to small, truncate apex, wall undifferentiated at apex, 8-spored, spores confined to upper half of ascus. Ascospores 21-29 x 2-3 µm (average 23.2 x 2.7 µm), in face view more or less cylindric, tapering from near the base toward the acute base, 0-septate surrounded by narrow gelatinous sheath.

Conidiomata subcuticular. In vertical section upper wall 5-10 µm thick, comprising dark brown material with no visible cellular structure. Lower wall of 1-3 layers of brown to dark brown, thick-walled, angular cells. Lower wall lined with 1-2 rows of hyaline, thin-walled cells on which the conidiogenous cells develop. Conidiogenous cells 10-15 x 1.5-2.0 µm, cylindric, tapering toward apex, with both sympodial and percurrent proliferation, no obvious thickening of wall at conidiogenous loci. Conidia 3-4.5 µm, straight, cylindric, ends rounded, hyaline.

ETYMOLOGY: named after type locality.

NOTES: Hypoderma dundasicum is very similar to the widespread H. rubi. The two species can be distinguished by ascospore size and shape, and ascus width. The appearance of the ascomatal wall in vertical section also differs, with the wall of H. rubi decreasing in width from the edge of the opening, while in H. dundasicum the uppermost part of the wall is more or less uniform in width. H. rubi has not been found on Ericaceae in New Zealand, although Powell (1974) reported it on ericaceous hosts from the northern hemisphere. H. gaultheriae Hunt, described on Gaultheria from North America by Hunt(1980) is reported to be associated with necrotic spots on green leaves, and has ascospores wider than those of H. dundasicum.

Ascomata subcuticular. In vertical section upper wall of unopened ascomata up to 50 µm thick, thinner toward the edges of the ascomata. Wall comprising mostly brown to pale brown, angular cells, darker toward the outside of the wall. In the inner half of the wall, along the future line of opening, is an ill-defined area of paler, thinner walled cells. Inside edge of the wall is lined with an irregular, 1-cell-wide layer of hyaline, cylindric to globose cells. In opened ascomata the upper wall is up to 80 µm thick near the ascomatal opening, becoming gradually thinner toward the base. Upper wall comprising brown to dark brown, thick-walled, globose to angular, 4-10 µm diam. cells. Exposed face of the broken upper wall is lined with a layer of hyaline, thin-walled, cylindric, 15-25 x 3-4 µm cells. Lower wall 8-15 µm thick, of 2-3 layers of brown, thick-walled, cylindric to angular, 3-6 µm diam. cells.

Paraphyses 1-2 µm diam., circinate at apex, extending 5-10 µm beyond asci. Asci 110-155 x 8.5-10.5 µm, clavate-stipitate, tapering to rounded apex, wall undifferentiated at apex, 8-spored, spores confined to upper half of ascus. Ascospores 24-38 x 2.0-2.5 µm (average 32.8 x 2.1 µm), cylindric-bifusiform, apex rounded, tapering to base, slight constriction near centre of the spore, hyaline, 0-septate, surrounded by narrow gelatinous sheath. Conidiomata subcuticular. In vertical section upper wall more or less lacking, or up to 5-8 µm thick, comprising dense, dark brown to black material with no obvious cellular structure. Lower wall 10-15 µm thick, of 2-3 layers of dark brown, thick-walled, cylindric cells. Lower wall lined with 2-3 layers of hyaline, thin-walled, angular cells on which the conidiogenous layer develops. Columns of sterile cells may extent between the upper and lower wall near the centre of the conidiomata. Conidiogenous cells 7.5-12.0 x 1.5-2.5 µm, more or less cylindric, proliferation percurrent, wall of conidiogenous cell slightly thickened and often flaring at the apical conidiogenous locus. Conidia 3-4 x 1-1.5 µm, cylindric, ends rounded, hyaline, 0-septate.

CHARACTERISTICS IN CULTURE: A few ascospores from PDD 43266 and PDD 46711 germinated on agar plates after48 hours. Colonies on OA 30-40 mm diam. after 8 weeks, aerial mycelium grey, dense, cottony to felted, agar surface dark brown near centre of colony, reddish toward edge with red pigment diffusing into agar around colony. Remaining sterile.

ETYMOLOGY: obtectum = covered over; refers to sparse layer of mycelium covering the upper wall of the ascomata.

NOTES: H. obtectum is easily distinguished from other New Zealand species by the wispy, yellow or white, aerial hyphae surrounding the ascomata, and by the size and distinctive shape of its ascospores.

Ascomata subcuticular. In vertical section upper wall of unopened ascomata up to 50-80 µm thick, comprising mostly brown to dark brown, thick-walled, angular cells, but near middle of the ascomata, along the future line of opening, the inside part of the wall comprises thinner-walled, paler cells. Wall starts to split open from outside edge, and as the split forms, hyaline, cylindric cells start to develop along the exposed face of the broken wall. In some hosts the split in the ascomatal wall may begin to develop prior to the covering host cuticle breaking. In opened ascomata the upper wall is 60-110 µm thick near the ascomatal opening, then becoming either abruptly, or gradually, thinner toward the outer edge, where it is 10-25 µm thick. Upper wall comprising dark brown, thick-walled, angular, 4-8 µm diam. cells. Exposed face of the broken upper wall is lined with cylindric, hyaline, thin-walled, 20-30 x 3-4 µm cells. Lower wall 10-15 µm thick, of 2-4 layers of dark brown, thick-walled, angular to globose,4-6 µm diam. cells.

Paraphyses 1.0-1.5 µm diam., circinate at apex, extending 5-15 µm beyond asci. Asci 110-160 x 11-14 µm, clavate-stipitate, tapering to small, truncate apex, wall often with small pore at apex, 8-spored, spores confined to upper half of ascus. Ascospores 15-28 x 2.5-5.5 µm (see notes below), in face view more or less naviculate in shape, widest point near centre, tapering slightly to rounded apex, and more sharply to acute base. In side view spores slightly curved. Spores surrounded by well-developed gelatinous sheath. Conidiomata subcuticular. In vertical section more or less globose in shape, upper wall 5 µm thick, comprising dark material with no obvious cellular structure, lower wall of 2-3 layers of dark brown, thick-walled, angular cells on which the conidiogenous layer develops. Conidiogenous cells 7-12 x 2-4.5 µm, tapering to apex, proliferating either sympodially, or rarely percurrently. Conidia 3-5 x 1-1.5 µm, cylindric, ends rounded, hyaline, 0-septate.

CHARACTERISTICS IN CULTURE: Spores germinated on agar plates within 24 hours. Cultures on OA 85 mm diam. after 6 weeks, aerial mycelium white to grey, sparse, agar surface pinkish to vinaceous brown, with scattered globose, black-walled conidiomata. Conidiomata splitting to expose grey conidial ooze. Conidiogenous cells and conidia as described from plant material.

Despite small differences, there is a strong overall similarity between the New Zealand collections and recent descriptions of H. rubi by Cannon & Minter (1986) and Powell (1974). The New Zealand collections show a wide range of ascospore length and width (15-28 x 2.5-5.5 µm), and also considerable variation between collections in average spore length and width. This variation correlates to some degree with host substrate. Ascospores taken from seven collections on Rubus spp. (both native and introduced) had a range of spore lengths confined to the upper end of the range for H. rubi as a whole, and spore widths confined to the lower end of the range of variation, with an average spore size of 24.1 x 3.3 µm. Spores from collections from native hosts, such as Pseudopanax spp. (16 collections, average spore size 19.6 x 3.9 µm), Griselinia spp. (6 collections, average spore size 19.5 x 3.8 µm), Olearia spp. (6 collections, average spore size 19.0 x 3.8 µm), and Coprosma spp. (6 collections, average spore size 19.4 x 4.3 µm), had spore lengths confined to the lower end of the range for H. rubi as a whole, and spore widths confined to the upper end of the range. Although there is overlap between the range of spore sizes from Rubus versus those from other hosts, both the ranges and the averages do differ. In all other characteristics of both teleomorph and anamorph the two groups cannot be distinguished. They are not recognized here as taxonomically distinct, however the differences in ascospore size may indicate that they represent genetically isolated populations.

Two distinct species, H. cordylines and H. dundasicum, very similar to H. rubi, have been recognised from New Zealand, primarily on the basis of ascospore shape and host preference. All the collections recognised here as belonging in H. rubi have more or less naviculate ascospores. The spores are widest near the centre, taper slightly to the rounded apex, and more markedly to the acute base. The ascospores of H. dundasicum are slightly narrower than those of H. rubi, are cylindric in shape, and although acute to the base, taper from only very close to the base itself. This character, which correlates with asci slightly narrower (8-11 µm wide) than those of H. rubi, has been seen in all collections on Ericaceae from New Zealand.

H. cordylines can be distinguished from H. rubi by ascospore shape, having elliptic or oblong-elliptic spores which are uniform in shape to both ends of the spore, and in having longer anamorph conidia. These characters have been seen in all collections examined from Cordyline and Phormium.

Fig. 10 A-F and Fig. 11 A show stages in ascomatal development of H. rubi. A similar pattern of development is found in all the Hypoderma spp. included in this paper. When first visible the developing ascomata comprise a lenticular shaped group of hyaline, plectenchymatous cells beneath which is the lower wall layer, comprising a single row of brown, thick-walled cells (Fig. 10 A). The lower wall under-goes more or less no change during subsequent stages of ascomatal development. At about the same time as the upper wall of the ascomata develops, a cavity forms within the hyaline plectenchyma, and paraphysis-like elements extend up into this cavity (Fig. 10 B, C). As the ascomata develop they increase in size, the upper wall becomes thicker toward the centre of the ascomata, the wall becomes internally differentiated, the paraphyses become longer, and asci begin to develop (Fig. 10 B, C, D). The upper wall comprises mostly brown, thick-walled, angular cells, but near the centre of the ascomata, in the inner half of the wall, is a wedge-shaped group of pale, thin-walled cells, and lining the inner edge of the wall is a layer of hyaline, short-cylindric, periphysoid-like cells (Fig. 10 D, E). The ascomatal upper wall starts to split open from the outside, and at the same time as the split develops, hyaline, thin-walled, cylindric cells form along the exposed face of the broken wall (Fig. 10 F), and in opened ascomata form a well-developed, persistent layer (Fig. 11 A). The periphysoid-like cells evident in immature ascomata are not visible in opened ascomata, presumably crushed by pressure exerted by the developing hymenium.

Ascomata subcuticular. In vertical section upper wall of unopened ascomata up to 70 µm thick, narrower toward edges, comprising mostly brown to dark brown, angular cells. Cells darker and thicker walled along outer edge of the wall, and along most of the inside edge. Along the future line of opening, toward the inside of the upper wall, is a group of paler, thinner-walled cells. In opened ascomata the upper wall is up to 70 µm thick near the ascomatal opening, becoming gradually thinner toward the base of the wall. Upper wall comprising brown to dark brown, thick-walled, angular, 4-8 µm diam. cells. Exposed face of the broken upper wall is lined with cylindric, hyaline, thin-walled, 30-45 x 4-5 µm cells. Lower wall 5-10 µm thick, of 2-3 layers of brown, thick-walled, angular, 4-7 µm diam. cells.

Paraphyses 1-2 µm diam., circinate at apex, extending 5-10 µm beyond asci. Asci 115-145 x 9.5-13.0 µm, clavate-stipitate, tapering to rounded apex, wall undifferentiated at apex, 8-spored, spores confined to upper half of ascus. Ascospores 22-38 x 3-4 µm (average 30.6 x 3.3 µm), sigmoid, tapering to base, 1-septate, surrounded by a narrow gelatinous sheath.

Conidiomata subcuticular. In vertical section upper wall 5 µm thick, comprising dense, dark brown material with no obvious cellular structure. Lower wall 10 µm thick, of 2-3 rows of brown, slightly thick-walled, angular to cylindric, 4-6 µm diam. cells. Lower wall is lined with 2-3 lavers of hyaline, thin-walled, angular, 3-4 µm diam. cells on which the conidiogenous cells develop. Conidiogenous cells 10-17 x 1.5-2.5 µm, cylindric or tapering to apex, percurrent proliferation, wall slightly thickened and sometimes flaring at the single, apical conidiogenous locus. Amongst conidiogenous cells near centre of the conidiomata is a group of hyaline, thin-walled, filiform, 2.5-3.5 µm diam. elements. Conidia 2.5-3 x 1 µm, elliptic-fusiform, pointed to both ends, hyaline, 0-septate.

CHARACTERISTICS IN CULTURE: Ascospores germinated on agar plates after 48 hours. Colonies on OA 45 mm after seven weeks, aerial mycelium sparse, white, cottony to tufted, agar surface with yellow tinge. After 13 weeks agar brownish in colour, black, globose, conidiomata-like bodies present, sterile.

ETYMOLOGY: sigmoideus = sigmoid; refers to shape of released ascospores.

NOTES: Hypoderma sigmoideum can be distinguished from. H. rubi, also found on Nothofagus solandri var. cliffortioides, both macroscopically and microscopically. The ascomata and conidiomata of both species are similarly shaped and sized, but the differentiated zone of cells lining the ascomatal opening in H. sigmoideum is reddish in colour, or if yellowish then turns red when treated with 3% KOH. The cells lining the ascomatal opening in H. rubi are yellow or brownish in colour and do not change colour in KOH. H. rubi has shorter, wider, 0-septate ascospores, and narrower asci which are truncate rather than rounded at the apex. The anamorphs of the two species differ in morphology of the conidiogenous cells, and in shape of the conidia.

Ascomata subcuticular. In vertical section upper wall of unopened ascomata up to 100 µm thick. Outer part of wall comprising dense, black material, in a layer up to 50 µm wide toward the centre of the ascomata, with the inner part comprising brown to pale brown, thin-walled, angular cells. In a narrow line, along the future line of opening, the paler cells extend almost to the outside of the wall. A few hyaline, thin-walled, cylindric cells line the inside of the wall. In opened ascomata the upper wall is up to 110 µm thick near the opening, becoming thinner toward the base, the outer part and the part of the wall near the ascomatal opening comprising dense, black tissue with no visible cellular structure; the inner part of pale, thin-walled, angular cells. The exposed face of the broken wall becomes lined with a layer of cylindric, hyaline to brown, thin-walled, 15-20 x 3-4 µm cells. Lower wall less than 5 µm thick, of one layer of dark brown, angular, thick-walled cells.

Paraphyses 1-2 µm diam., undifferentiated at apex, barely extending beyond asci. Asci 120-160 x 17-22 µm, clavate, becoming clavate-stipitate prior to spore release, tapering to truncate apex, wall slightly thinner across apical part of ascus, 8-spored. Ascospores 24-39 x 3.5-5 µm (average 33.4 x 4.1 µm) bifusiform, 1.5-2.0 µm wide at central constriction, 1-septate, surrounded by gelatinous sheath. Ascospores within the ascus often breaking across the central septum into two part-spores. When this occurs ascoconidia are produced from the broken end of each part-spore, and the asci eventually become full of the 4.0-7.5 x 1.0-1.5 µm, cylindric, 0-septate, hyaline ascoconidia.

Conidiomata subcuticular. In vertical section lenticular in shape. Upper wall 5-10 µm thick, comprising dark brown tissue with noo bvious cellular structure. Lower wall 5-15 µm thick, of 1-3 rows of dark brown, thick-walled, angular cells. Conidiogenous layer develops on lower wall. Conidiogenous cells 8-13 x 1.5-2.5 µm, cylindric, tapering near apex, wall slightly thickened at the single, apical conidiogenous locus, proliferation percurrent. Conidia 3.5-4.5 x 1.0-1.5 µm, oblong-elliptic, 0-septate, hyaline.

ETYMOLOGY: named after host substrate.

NOTES: This is the only Hypoderma species in New Zealand known from a fern. It is easily distinguished from other species by its large ascomata, black-walled conidiomata, large asci, and by its 1-septate, often disarticulating ascospores. The appearance of the upper wall of unopened ascomata is distinctive with its broad inner layer of pale, thin-walled cells.