Ionaspis lacustris
Common name
Rusty brook lichen
Family
Hymeneliaceae
Flora category
Lichen – Native
Endemic taxon
No
Endemic genus
No
Endemic family
No
Structural class
Lichens - Crustose
Current conservation status
2018 | Data Deficient | Qualifiers: SO
Brief description
Characterised by the saxicolous habit; the subimmersed, mosaic-forming creamish white to rust-red thallus; the pinkish to orange, aspicilioid apothecia; and globose to broadly ellipsoidal ascospores, 13–20 × 6–11 μm.
Distribution
South Island: Otago (Mt Cargill); Southland (Crombie Stream Waitutu Forest). Campbell Island.
Known also from Great Britain, Europe, Scandinavia, North and South America and Australia.
Habitat
On hard, siliceous rocks in stream beds, often ±immersed or inundated; often forming an extensive zone of mosaics with aquatic species of Anisomeridium, Porina, Staurothele, Strigula and Verrucaria.
Detailed description
Thallus 0.1–0.4 mm thick, smooth, ±even, continuous to cracked (noticeably around apothecia), pale whitish cream or greenish to deep rust-red, effuse or forming mosaics and then delimited by red-brown prothalline lines. Apothecia 0.15–0.4(–0.6) mm diam., often crowded, ± immersed, or with a slightly raised proper exciple, rounded to subirregular, pale-pink to bright-orange when wet, becoming pale-orange to red-brown on storage. Proper exciple ±colourless, the upper and outer parts pale-brown to red-brown. Epithecium pale-orange to dark red-brown, inspersed with minute granules, not dissolving in K. Hymenium 90–105 μm tall. Ascospores broadly ellipsoidal to ±globose, 13–20 × 6–11 μm. Pycnidia 50–80 μm diam., red-brown. Conidia 4.5–6.5 × 1 μm.
Substrate
Saxicolous
Etymology
lacustris: From the Latin lacus ‘lake’, meaning growing beside a lake
The genus Ionaspis is included in the family Hymeneliaceae (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 Ionaspis suaveolens group, the I. odora group and the I. lacustris group. One species, I. lacustris, is known from New Zealand. This species is frequently infected by lichenicolous fungi, and colonies are often infected by more than one species.
Attribution
Fact sheet prepared by Melissa Hutchison (4 September 2021). Brief description, Distribution, Habitat, Features, and Extra information sections copied from Galloway (2007).
References and further reading
Eriksson O.E. (Ed.) 2005: Outline of Ascomycota – 2005: Myconet 11: 1-113.
Eriksson O.E., Baral H.-O., Currah R.S., Hansen K., Kurtzman C.P., Rambold G. & Laessøe T. 2004: Outline of Ascomycota – 2004. Myconet 10: 1-99.
Galloway D.J. 2007: Flora of New Zealand: Lichens, including lichen-forming and lichenicolous fungi. 2nd edition. Lincoln, Manaaki Whenua Press. 2261 pp.
Lutzoni F.M. & Brodo I.M. 1995: A generic redelimitation of the Ionaspis-Hymenelia complex (lichenized Ascomycotina). Systematic Botany 20: 224-258.
Pennycook S.R. & Galloway D.J. 2004: Checklist of New Zealand “Fungi”. In: McKenzie, E.H.C. (Ed.) Introduction to fungi of New Zealand. Fungi of New Zealand/Ngā Harore o Aoteroa Volume 1. Fungal Diversity Research Series 14: 401-488.