Flora of New Zealand Series

Type : Ionaspis chrysophana (Körb) Th.Fr. ex Stein. [=Aspicilia chrysophana Körb. For details of typification see Lutzoni & Brodo (1994: 657; 1995: 252–253)].

Description : Thallus crustose, epilithic, continuous or cracked to areolate, pinkish white, pale-yellow-pink, grey-brown, olive-grey, to pale-orange, orange-yellow, yellow-brown to brown. Photobiont green, trebouxioid or Trentepohlia. Ascomata apothecia, aspicilioid, immersed within thallus or substratum, discs rounded, subangular or irregular, concave to flat, reddish orange, red-brown, grey-brown, dark-brown, dark-grey to black. Lateral and basal proper exciple present (photobiont cells absent), hyaline to variously coloured, orange, orange-yellow, brown-black, olive-brown to dark-green. Hymenium (45–)75–115 (–160) μm tall, hyaline, orange-yellow, greyish olive to dark-green. Hamathecium of paraphyses, simple to branched and anastomosing above, moniliform, slightly swollen at apices. Hypothecium hyaline to pale yellowish brown. Asci cylindrical–clavate, 8-spored, apex I−. Ascospores globose to ellipsoidal, simple, colourless, not halonate. Conidiomata pycnidia, immersed. Conidia simple, colourless, bacillar to filiform.

The genus Ionaspis is included in the family Hymeneliaceae (Lutzoni & Brodo 1995; Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005) and comprises some 10 taxa of freshwater, aquatic lichens found mainly in temperate, boreal–hemiboreal and/or arctic-alpine environments of the Northern Hemisphere. Species occur submerged in small creeks or streams or on riverbank boulders and stones, in the spray zone of waterfalls, on the rocky shores of lakes, or on small boulders of siliceous rocks in forest. The genus and its separation from the related genera of Hymenelia, Eiglera and Aspicilia is discussed by Lutzoni & Brodo (1995), who recognised three distinct species groupings within Ionaspis. These are: the I. suaveolens group, the I. odora group and the I. lacustris group. One species, I. lacustris, is known from New Zealand (McCarthy & Johnson 1995, 1998; Johnson & McCarthy 1997). This species is frequently infected by lichenicolous fungi, and colonies are often infected by more than one species. In a recent account, Orange (2002) records eight lichenicolous taxa from European specimens of I. lacustris, including the genera * Endococcus, * Kalaalia, * Muellerella, * Polycoccum, * Sagediopsis, * Verrucaria and * Zwackhiomyces.