Specimens examined: Chatham Islands: Rekohu, Tennants Lake, 7.III. 1983, E. H. C. McKenzie (PDD 44183 - holotype); ibid., 5.III.1983, E. H. C. McKenzie (PDD 44224); Blind Jims Creek, 9.III.1983, E. H. C. McKenzie (PDD 44179, PDD 44180).

Mycelium immersed, hyaline, branched, smooth, septate, 3-5 µm thick. Ascomata solitary, immersed and developing in cavities in leaf, short papillate, subglobose or globose, 60-130 µm diam., 95-140 µm high, ostiolate; ascomatal wall 2-4 cells thick, uniform in width, 5-8 µm wide; cells forming a textura angularis, thin walled, pale yellowish. Asci cylindrical or clavate, 85-110 x 15-20 µm, short pedunculate, unitunicate, thick walled at apex, with a non-amyloid cone-shaped apical annulus. Ascospores biseriate, subhyaline, pale yellowish in mass, 2-septate, with one median septum and the other in the lower half, usually slightly constricted at septa, oval or fusiform, straight or slightly curved, apex obtuse, base obtuse or acute, (28-) 30-37 (-38) µm long, (8-) 8.5-10 (-11) µm wide. Conidiophores semi-macronematous, mononematous, single, unbranched, geniculate, smooth, aseptate, hyaline, up to 30 µn long, 5-11 µm wide, arising from swollen hyphal cells within the epidermal cells of the host, and perforating the cuticle and outer wall of the epidermal cells. Conidiogenous cells polyblastic, integrated, terminal, sympodial. Conidia solitary, acropleurogenous, subhyaline, pale yellowish in mass, smooth, medianly 1-septate, straight or slightly curved, obclavate, (39-) 50-65 (-70) µm long, (8) 9-10.5 (-11.5) µm wide, apex obtuse, base truncate.

On Carex sinclairii Boott

Mycelium intermum, ex hyphis, hyalinis, ramosis, laevibus, septatis, 3-5 µm crassis. Ascomata solitaria, interma, subglobosa vel globosa, 60-130 µm diam., 95-140 µm alta, ostiolata, papillata; tunica 5-8 µm lata, 2-4 stratis cellularum composita, texturam angularem formans; cellula tenuitunicata, pallide lutea. Asci cylindrici vel clavati, 85-110 x 15-20 µm, breve pendunculati, unitunicati, pariete ascorum apicaliter crasso; corpora apicali, conico, annulari. Ascosporae biseriatae, subhyalinae, medio et infra septatae, ad septa plerumque leviter constrictae, rectae vel leviter curvatae, ovales vel fusiformes, apice obtusae, basi obtusae vel acutae, (28-) 30-37 (-38) µm longae, (8-) 8.5-10 (-11) µm crassae. Conidiophora semi-macronematosa, mononematosa, singula, eramosa, geniculata, laevia, eseptata, hyalina, usque ad 30 µm longa, 5-11 µm crassa. Cellulae conidiogenae polyblasticae, in conidiophoris incorporatae, terminales, sympodiales. Conidia solitaria, acropleurogena, subhyalina, laevia, 1-septata, (39-) 50-65 (-70) µm longa, (8-) 9-10.5 (-11.5) µm late, recta vel leviter curvata, obclavata, apice obtusa, basi truncate.
In foliis cyperaceae speciei Carex sinclairii Boott et Carex virgata Boott.

Associated with a leaf spot. On Carex sinclairii producing pale oval lesions up to 8 mm long, with a distinct border. On Carex virgata producing elongate, dark brown lesions, coalescing and covering large parts of the leaf.
Two species of Buergenerula are known on Carex species; B. biseptata (DC. ex Mérat) Speer described from Europe, and B. caricis (Sprague) Arx ( Yukonia caricis Sprague) described from Alaska. Barr (1976) considered these two species to be identical, but von Arx (1977) regarded them as distinct. Conidia have apparently only been recorded on the single Alaskan specimen, although they are present on all five specimens from New Zealand. Paraphyses were not seen in B. zelandica, but Barr(1976) described them for B. biseptata as being broadly cellular, thin-walled and fragile.
Both ascospores and conidia of B. zelandica are somewhat longer than those described by Barr for the European fungus and for the fungus from Alaska. Barr gave ascospore measurements of (19-) 22-27 (-30) x 6-8 (-10) µm, and conidial measurements of (32-) 35-42 (-50) x 9-13 µm. In addition, she described and figured the conidia as obovate and more or less truncate at the apex. This appears to be an error, for both Sprague (1962) and von Arx (1977) described the conidia as obclavate and truncate at the base.

Holotypus PDD 44183.