SPECIMEN EXAMINED: NEW ZEALAND: AUCKLAND ISLANDS: on Hebe odora (as Veronicaodora), K (M 85260) ex Herb. Berk. - Holotype ofDothidea hemisphaerica.

The type specimen comprises a few fragments of leaf, with 2 ascomata, one cut in half. Ascomata on lower surface of leaves, forming black, tar-spot-like symptoms, round in outline, 1.2-1.5 mm diam.,raised, hemispherical, up to 0.5 mm high, tapering suddenly toward the slightly inrolled margin. Surface black, slightly sculptured in appearance due to pseudothecial mounds. Outermost tissue of ascoma black, lined with globose to slightly cylindric pseudothecia about 80-100 µm diam., ascomatal tissue beneath pseudothecia very dark brown, base of ascoma has what appears to be a black lower wall. Ascomatal tissue releasing a bluish pigment in KOH. Ascospores 21.5-25 x 6.5-7.5 µm, cylindric, 1-septate, constricted slightly at the more or less central septum, upper cells slightly wider than lower, wall dark brown, smooth to finely punctate. Asci and paraphyses not seen.

DISCUSSIONAlthough the only material of Clypeostroma hemisphaericum available is fragmentary, this species is clearly distinct from C. spilomeum. They differ in macroscopic appearance of the ascomata, in ascomatal structure, and in ascospore size and colour.They are probably specialised toward different hosts. The differences in ascomatal structure suggest they belong in different genera. C. hemisphaericumhas a true stromatic ascoma with a distinct lower wall and uniformly dark (probably fungal) internal tissue, whereas the internal tissue of the raised ascoma of C. spilomeum comprises mostly host cells beneath a clypeus-like layer. Without additional material ofC. hemisphaericum, allowing examination of asci,hamathecial tissues, and ascomatal insertion, it is not possible to speculate on where this species may be better placed. C. spilomeum is the type species of the genusClypeostroma. While its asci are typical of the fissitunicate ascomycetes, where it belongs amongst these fungi is uncertain. The lack of hamathecial tissue suggests a relationship with the Dothideales sensu Barr (1987), but the immersed, globose, thinwalled pseudothecia aggregated beneath a common, subcuticular clypeus appears to fit no family within this taxon. Ascomatal structure is similar to some taxa within the Venturiaceae. For example,Sivanesan (1977) discussed a group of Venturia species with a clypeus above the more or less globose, thin-walled pseudothecia. Venturia, however,is characterised by the formation of filamentous pseudoparaphyses, and typically the ascomata develop on dead tissue as an overwintering phase in the life cycle. I retain C. spilomeum in Clypeostroma,but suggest no relationship for it amongst the bitunicate ascomycetes.

SPECIMENS EXAMINED: NEW ZEALAND: AUCKLANDISLANDS: on Hebe elliptica (as Veronica elliptica), K (M 85261) ex Herb. Berk. - Holotype of Dothidea spilomea; on H. elliptica (as V. elliptica), J. D. Hooker, PDD 61540 ex Reliquiae Petrakianae 821 - Isotype of Dothidea spilomea;Ewing Island, on H. elliptica (as V. elliptica), J. Kirk 338, K (M 85262) - Holotype of Rhytisma discoidea; Enderby Island, Sandy Bay, on H. elliptica, P. R.Johnston AK65, 21 Mar 2000, PDD 73062. CAMPBELL ISLAND: Shoal Point, on H. elliptica,P. R. Johnston CAM 157 & S. L. Stephenson, 16 Mar 2000, PDD 73063; Mt Honey, on H. elliptica, P. R.Johnston CAM 165 & E. H. C. McKenzie, 7 Mar 2000, PDD 73064. STEWART ISLAND: Deep Cove, on beach, on H. elliptica, P. R. Johnston & E. M. Gibellini, 11 Jan 1998, PDD 68726; DeepCove, on beach, on H. elliptica, P. R. Johnston &E. H. C. McKenzie, 19 Nov 1998, PDD 69731; Ulva Island, Boulder Beach, on H. elliptica, P. R. Johnston & E. H. C. McKenzie, 21 Nov 1998, PDD 69732. NORTH ISLAND: Wellington, on Hebe sp.(as Veronica sp.), H. Cockayne, 1908, PDD 451.

Ascomata developing and maturing on lower surface of living leaves, forming black, tar-spot-like symptoms, more or less round in outline, 0.7-1.4 mm diam., slightly raised, tapering gradually to margin,often with numerous ascomata on a single leaf; no chlorosis of surrounding leaf tissue. Ascomatal surface black, more or less smooth, with tiny, round ostioles barely visible. Ascomata subcuticular, not becoming erumpent, with several pseudothecia covered by a single clypeus. Pseudothecia more or less globose, 70-80 µm diam., wall 8-10 µm thick, comprising 2-3 rows of cylindric, flattened cells with pale brown, thin walls; opening through a simple, round ostiole at apex. Upper part of pseudothecial wall merging with clypeus. Clypeus subcuticular, up to 35 mm thick, comprising 3-4 rows of angular cells with dark, thick walls. Scattered hyphae with thin, hyaline walls forming beneath clypeus, between and below pseudothecia and amongst the largely intact cells of the host leaf. Asci 90-105 x 15-20 µm, cylindric to subsaccate, tapering abruptly to small, foot-like base, and gradually to rounded apex, fissitunicate, 8-spored. Ascospores (23-)25.5-34.5x 6-7 µm, cylindric, 1-septate, constricted slightly at the more or less central septum, upper cell slightly wider than lower, rounded at apex and base, wall becoming pale brown, sometimes finely punctate.Paraphyses not seen.