Ascomata subcuticular. In vertical section the ascomatal initial comprises a lens-shaped group of hyaline, plectenchymatous cells oriented more or less parallel to the surface of the host leaf, with darkened, angular cells developing toward the lower surface of the plectenchyma. As the ascomata develop, and paraphyses start to differentiate, darkened angular cells begin to develop along the upper as well as the lower edge of the ascomata. As the paraphyses elongate and asci begin to develop the upper wall of the ascomata becomes up to 60 µm thick near the centre of the ascomata, narrower toward the edges. The upper wall comprises mostly brown to dark brown, thick-walled, angular cells, but near the centre of the ascomata, along the future line of opening, toward the inside of the wall, is a group of hyaline thin-walled, angular cells. The inside of the wall is lined with a poorly developed layer of hyaline, thin-walled, short-cylindric, downward-oriented cells. In some ascomata the upper wall retains this appearance until opening, but in others, at about the stage when ascospores are first starting to differentiate, the cells along the lower part of the pale area along the future line of opening become darkened and thick-walled. At about the same stage of development, some ascomata develop an extra layer up to 20 µm thick, of hyaline, thin-walled, vertically oriented cells between the upper wall and the host cuticle. The upper wall starts to split open from the outside, and as the wall splits a layer of thin-walled, hyaline, cylindric cells develops along the exposed face of the broken wall. In opened ascomata the upper wall is up to 100 µm thick near the opening, becoming narrower toward the edge of the ascomata, and comprises brown to dark brown, thick-walled, angular cells. The exposed face of the broken upper wall is lined with a palisade-like layer of thin-walled, 10-15 x 1-2 µm, cylindric cells. The layer between the upper wall and the cuticle present in some ascomata is retained after the ascomata open. In opened ascomata the lower wall is 5-10 µm thick, comprising 1-3 layers of brown to dark brown, angular to cylindric cells.

Paraphyses 1.5-2.5 µm diam., undifferentiated at apex, extending 15-25 µm beyond asci. Asci 130-200 x 18-22 µm, clavate to subsaccate, tapering to truncate apex, wall more or less undifferentiated at apex, 8-spored, development of asci sequential. Ascospores 40-70 x 5.5-8 µm, bifusiform, 1.5-2.5 µm wide at constriction, 0-1 septate, surrounded by a 2-4 µm thick gelatinous sheath. Conidiomata 0.2-0.3 mm diam., round in outline, pale brown, with a darker line around the outside edge, subcuticular. In vertical section the upper wall is more or less absent. Lower wall 5-10 µm thick, comprising 2-3 layers of brown to dark brown, thick-walled, angular cells. Conidiogenous cells develop on the lower wall, 6-10 x 2-3 µm, solitary, cylindric, with percurrent proliferation, wall of the conidiogenous cell thickened and often slightly flaring at the single, apical conidiogenous locus. Amongst the conidiogenous cells, near the centre of ascomata, are narrow-cylindric, hyaline, sterile elements extending almost to the top of the conidiomata. Conidia 4-6 x 1 µm, cylindric, ends rounded, nonseptate, hyaline.

CHARACTERISTICS IN CULTURE: Ascospores germinated from PDD 43973 and 57549 on agar plates, on oatmeal agar colonies 20-30 mm diam. after 5 weeks, surface of colony undulate, pale brown, aerial mycelium low, felted, white, or lacking, pale brown in reverse.

ETYMOLOGY: refers to the liliaceous host substrate.

NOTES: This is the only species of Rhytismataceae known from Collospermum, but Coccomyces limitatus, Lophodermium asteliae, and L. minus are known also from Astelia. Hypoderma liliensis is easily distinguished from these other species by the bluish differentiated zone along the edge of the ascomatal opening, and microscopically by the large, subsaccate asci, and bifusiform ascospores.

Although the ascus shape, and ascus and ascospore size, are unusual for Hypoderma, H. liliensis possesses all the characters used by Johnston (1990) to redefine this genus. Also atypical of Hypoderma is the darkening of the inner edge of the upper wall seen in some collections of this species, but as this feature is not found consistently in all collections, it is not considered of generic significance. The development of a layer of hyaline, cylindric cells between the upper wall and the cuticle is also unusual. However, a similar phenomenon has been seen in a few collections of Hypoderma rubi (Persoon:Fries) de Candolle ex Chevallier from New Zealand, although the layer of cells in this case is not as well developed as in H. liliensis, and it forms later in the development of the ascomata, appearing only shortly before the ascomata open.

The size and shape of the asci and ascospores of H. liliensis are similar to those of Duplicaria empetri (Persoon:Fries) Fuckel and many of the conifer-inhabiting species of Rhytismataceae. Duplicaria differs in having circular ascomata with radiate opening splits, and an upper wall with no internal differentiation in unopened ascomata, barely thickened toward the opening, and with no cylindric, thin-walled cells lining the exposed face of the broken upper wall in opened ascomata. The conifer-inhabiting species with similar ascospores and asci differ in having ascomata which develop subepidermally, which lack a darkened lower wall, and lack differentiated cells along the edge of the opening split. The one conifer-inhabiting genus with large, bifusiform ascospores and subcuticular ascomata, Bifusella, has synchronous development of the asci, and lacks persistent paraphyses.

Ascomata initially subepidermal, epidermal cells becoming filled with fungal tissue as ascomata mature. Scattered fibre cells from the host leaf become trapped within the walls of the developing ascomata. In vertical section ascomata initially comprising rows of vertically oriented, hyaline cells, with the lowermost cells becoming dark brown and thick-walled. Paraphyses develop within a central cavity and, as they elongate, the lower wall becomes darker, and the epidermal cells become filled with angular, thick-walled, dark brown fungal cells. In opened ascomata both the upper and lower walls are almost entirely composed of very dark tissue with no obvious cellular structure, intermixed with fibre cells of the host leaf. A few pale, thin-walled, cylindric cells remain at the sides of the hymenium.

Paraphyses 1-1.5 µm diam., undifferentiated at apex, not extending beyond asci. Asci 70-80 x 5-6.5 µm, cylindric to subclavate, tapering slightly to broad, truncate apex, wall unthickened at apex, sometimes with small, central pore, development sequential, 8-spored, spores confined to the upper 40-50 µm of the ascus. Ascospores 30-35 x 1.5 µm, tapering toward both ends, curved or coiling on release, 1-septate, with no obvious gelatinous sheath. Conidiomata 0.3 mm diam, round in outline, pale brown with darker line around outside edge. In vertical section lenticular in shape, both upper and lower walls 5-10 µm thick, of 1-3 layers of brown to dark brown, slightly thick-walled, angular cells, the cells of the lower wall darker than those of the upper. Both upper and lower walls lined with 1-2 rows of hyaline, thin-walled cells, on which the solitary conidiogenous cells are formed. Conidiogenous cells 8-12 x 1.5-2.5 µm, cylindric or tapering to apex, proliferating sympodially, often with two developing conidia held at apex. Conidia 3-4 x 1 µm, oblong-elliptic with rounded ends, 0-septate, hyaline.

ETYMOLOGY: nematoideum = nematode-like, refers to shape of released ascospores.

NOTES: Macroscopically L. nematoideum is typical of the group of species with the pattern of ascomatal development matching L. minus (Tehon) Johnston (Johnston 1989a (as L. multimatricum Johnston), 1989b). It is easily distinguished microscopically from the other species in this group by ascospore shape and size, but is indistinguishable macroscopically from L. minus and L. breve (Berkeley) de Notaris, both also found on Gahnia.

Ascomata develop beneath the epidermal cells and the fibre bundles on the outside of the leaf. In vertical section the upper wall is about 10 µm thick near the base, up to 60 µm thick near the top, and comprises brown to pale brown, thin-walled, cylindric, 2-3 µm diam. cells, intermixed with scattered clumps of crystals. The part of the wall adjacent to the hymenium is lined with a layer of inward-projecting, cylindric, hyaline, 10-15 x 1-2 µm, periphysis-like cells. Fungal hyphae ramify amongst the partially broken down host tissue covering the ascomata. The lower wall is 10-15 µm thick, of thin-walled, brown to pale brown, cylindric cells.

Paraphyses 1-1.5 µm diam., often with short, irregular, propoloid branches near the apex, intermixed with crystals, not extending beyond asci. Asci 80-110 x 7.5-9 µm, more or less cylindric, tapering gradually to more or less rounded apex, wall undifferentiated at apex, 8-spored. Ascospores 60-75 x 2-3 µm, filiform-subspathulate, the widest point near the apex but tapering rapidly distally, with the rest of the spore uniform in diam., 1-septate, gelatinous cap at both ends.

CHARACTERISTICS IN CULTURE: Ascospores of PDD 48570 germinated on agar plates, on oatmeal agar colonies 15-20 mm diam. after 5 weeks, aerial mycelium, low, felted, white toward edge of colony, pale pink toward centre, pinkish in reverse.

ETYMOLOGY: from host genus.

NOTES: P. desmoschoeni is the only species of Rhytismataceae known from Desmoschoenus, a sand dune inhabiting sedge. It is very similar to P. dendrobii, described from New Zealand on Dendrobium (Johnston 1986). Both species have ascomata with dark walls, asci and ascospores about the same size, and ascospores with a distinctive swelling in the upper half. P. dendrobii differs in having ascospores with the swelling adjacent to the septum, close to the centre of the spore, rather than near the apex. In addition P. dendrobii has ascomata with radiate opening slits, rather than a single longitudinal slit. This difference may simply reflect the different textures of the host substrates, the leaves of Desmoschoenus having a stronger linear structure than Dendrobium.

ETYMOLOGY: from the Maori language, pureke (pu.re.ke) = knob, refers to shape of paraphysis apex.

Pureke has all the features typical of the family Rhytismataceae (sensu Cannon & Minter 1986), and within the family is characterised by the following features:
- ascomata elliptic in outline with a single, longitudinal opening split;
- ascomata subepidermal;
- the ascomata develop a darkened lower wall at an early stage in ascomatal development, before the differentiation of paraphyses or the development of a darkened upper wall;
- in unopened ascomata the upper wall is mostly composed of dark, thick-walled cells, but has a line of pale, thin-walled cells along the future line of opening;
- in opened ascomata a layer of thin-walled, cylindric cells develops across the exposed face of the broken upper wall.
- paraphyses persistent, swollen, knob-like at the apex;
- asci clavate-stipitate, developing sequentially.

The generic description is based on features associated with the development and anatomy of the sterile tissues of the ascomata. As discussed by Johnston (1990) these characters are considered more useful for defining "natural" groups within the Rhytismataceae than ascospore shape, traditionally used at the generic level in this family.

Pureke is similar to Hypoderma (sensu Johnston 1990) in macroscopic appearance of the ascomata, ascus shape, and ascospore shape, but differs from Hypoderma in three of the nine characters listed by Johnston (1990) as important at the generic level. The ascomata of Pureke are subepidermal rather than subcuticular; in unopened ascomata, the zone of pale cells along the future line of opening extends all the way through the wall, rather than being confined to the inner part of the wall; and the paraphyses are swollen-clavate at the apex rather than unswollen.

Because of the importance other authors have placed on ascospore shape in the taxonomy of the Rhytismataceae, I will compare Pureke to other genera in this family with bifusiform ascospores. The three conifer-inhabiting genera with bifusiform ascospores, Bifusella Höhnel, Isthmiella Darker, and Solleela Darker, all have ascomata lacking a darkened lower wall, lacking differentiated cells along the edge of the opening split, and either lacking paraphyses or having paraphyses undifferentiated at the apex. Their asci are saccate to subsaccate in shape, and are often synchronous in development. Two other genera with bifusiform ascospores, Duplicaria Fuckel and Bifusepta Darker, are found on Ericaceae. Duplicaria has circular ascomata with radiate opening splits, the upper wall of the ascomata with no internal differentiation, and no differentiated cells along the edge of the opening split, saccate to subsaccate asci, and paraphyses undifferentiated at the apex. Bifusepta occurs on wood, has a very thick lower wall, and a distinctive upper wall structure, as discussed by Powell (1973).

Ascomata initially subepidermal, but often the epidermal cells becoming filled with fungal cells as the ascomata mature. In vertical section, at a stage when paraphyses are first differentiating, the upper wall is 20-30 µm thick, comprising 4-6 rows of hyaline to pale brown, thin-walled, angular cells. At the same stage the lower wall is 5-15 µm thick, comprising 1-3 rows of brown to dark brown, thick-walled, angular cells. As the ascomata mature the upper wall becomes darker and thicker, while the lower wall remains more or less unchanged. Prior to opening, the upper wall of the ascomata is up to 60 µm thick, slightly thinner toward the edges, and comprises mostly dark brown, thick-walled, angular cells, but with a line of pale, thin-walled cells extending through the wall along the future line of opening. A patch of very dark tissue, in which the cellular structure is obscured, develops in the inner half of the wall adjacent to the paler cells marking the future line of opening. In opened ascomata the upper wall is 60-80 µm thick, comprising mostly dark brown, thick-walled, angular cells, but with a patch of very dark tissue in the inner half of the wall near the ascomatal opening. The exposed face of the broken upper wall is lined with a persistent palisade-like layer of thin-walled, pale, cylindric cells.

Paraphyses 1.5-2 µm diam., increasing in width suddenly to 6-10 µm at the knob-like apex, extending 10-15 µm beyond asci. Asci 140-185 x 11-14 µm, clavate-stipitate, tapering to small, rounded apex, wall undifferentiated at apex, 8-spored, spores confined to upper half of ascus, development of asci sequential. Ascospores 35-60 x 2.5-3.5 µm, apex rounded, tapering to base, bifusiform, with abrupt constriction to 1-1.5 µm diam. near centre, 0-1 septate, surrounded by a gelatinous sheath.

Conidiomata-like structures 0.2 mm diam., round in outline, pale brown with darker line around outside edge, subepidermal. In vertical section lenticular, upper wall lacking, lower wall 5-10 µm thick, of 1-3 rows of dark brown, thick-walled, angular cells. Conidiogenous cells and conidia not seen.

ETYMOLOGY: refers to geographic distribution of this species.

NOTES: The distinctive shape of the ascospores and of the paraphysis tips makes this an easy species to identify microscopically. It is the only species of Rhytismataceae known from Dacrycarpus, but it could be confused macroscopically with others on Nothofagus menziesii (e.g., Lophodermium medium Johnston) and Knightia excelsa (e.g., Lophodermium brunneolum Johnston).

The collection on Dacrycarpus had longer ascospores (45-60 µm) than all the other collections (35-45 µm). However, as this was the only morphological difference between the collections it is considered to represent variation within a single species.

The occurrence of one species on both conifer and angiosperm hosts is unusual in the Rhytismataceae. However, within New Zealand this kind of host distribution is also seen with the species Lophodermium agathidis and L. mahuianun (Johnston 1989a).