Flora of New Zealand Series

Thallus filamentous, tufted, in small pulvinate rosettes, or irregularly straggling, by small holdfasts. Branches of filaments paired, apices discrete, hyphae in a rectangular arrangement of forming an irregular network, both types arising from a basal strand. Basal strand of hyphae distinct in younger parts of thallus, persistent in some species. Photobiont blue-green, Scytonema. Apothecia lateral, disc brown or dark green, with a thalline margin, concolorous with thallus. Paraphyses either richly branched and anastomosing paraphysoids (primary paraphyses) or distinctly septate, true paraphyses (secondary paraphyses). Asci prototunicate, cylindrical, clavate or obclavate, 8-24 or more-spored. Ascospores simple, often with a plasma bridge, colourless. Pycnidia lateral, the ostiole brown or dark green. Conidia small, rod-shaped, developing from the tips of unbranched elongated conidiophores.

Zahlbrucknerella, a genus of filamentous lichens in the family Lichinaceae, contains 7 described species. Two species (one undescribed) are found in New Zealand on calcareous rocks in subalpine localities of South I., and may be more widespread. Species form characteristic small, black tufts on damp rocks often along drainage channels or cracks. Zahlbrucknerella is close to Ephebe, another genus of filamentous lichens in the Lichinaceae but is distinguished from it by differences in ascocarp development (Ephebe has pycnoascocarps - Zahlbrucknerella has apothecia derived from a hyphal web of generative tissue) and in the photobiont (Stigonema in Ephebe - Scytonema in Zahlbrucknerella). Both genera include polysporous species; in Ephebe there are 8 or 16 spores in the ascus, in Zahlbrucknerella 24 spores are the general rule, with only one species having 8-spored asci [Henssen Symb. bot. upsal. 18: 77-81 (1963); Henssen and Jahns "Lichenes..." George Thieme, Stuttgart, pp. 330-335 (1937); Henssen Lichenologist 9: 17-46 (1977)].

The centre of evolution of species in Zahlbrucknerella appears to be on the American continent (Henssen 1977, loc. cit. ). Four of the seven described species are confined to North or South America. One species is endemic to South Africa. Two species, one fertile and one sterile, were found in New Zealand during the IAL excursion to inland Canterbury (September 1981) from calcareous rocks in the gorge of Cave Stream.