Coniocarpon cuspidans
Coniocarpon cuspidans is a species of the boreo-nemoral rainforests and oceanic woodlands in from Vest-Agder to Vestland. It is characterized by the elongate to lirellate, dark purplish-brown apothecia without orange red or white pruina. The pale brown spores are (3–)4–5(–8)-transversely septate and have an enlarged apical cell.
- Innhold
- Description
- Ecology
- Distribution in Norway and the Nordic countries
- Global distribution
- Similar species
Description
Thallus
The thallus is off-white to fawn and has a matt to weakly glossy, compact surface. It is immersed in the bark to superficial. The margin is not determinate or delimited by a thin brown line, mainly when in contact with other lichen thalli. The photobiont is a species of the family Trentepohliaceae.
Fruitbodies
The apothecia are raised over the thallus surface and typically clearly elongated, lirellate or branched. They are dark purplish brown in color, and lack the orange red or white pruina of the other Coniocarpon species. Individual lirellae are 0.2–0.6 × 0.1–0.2 mm in size and 60–105 μm tall. They are often aggregated in loose or dense stare-shaped clusters reaching 2.3 × 1.8 mm in size.
The epithecium is 8–20 μm tall, dark brown, and includes numerous unpigmented crystals in addition to orange, red and purplish granular pigment.
The hymenium is 40–75 μm tall and colorless except for the occasional weak and patchily distributed red to purplish pigmentation.
The hypothecium is colorless to pale brown and 15–30 μm tall.
The paraphysoids are 1–2 μm wide. Their tips are widened to 3–4 μm and extend horizontally above the asci. The tips often protrude from the epithecium to form sparsely branched hair-like extensions up to 10 μm in length. The hyphal walls contain patchily distributed brown pigment.
The asci are clavate, with stipe, 45–70 × 19–28 μm in size, and 8-spored.
The spores are colorless, narrowly obovoid, (15–)16–18(–20) × (6–)7–8(–9) μm in size, and are divided by (2–)3(–4) transverse septa. The apical cell is enlarged. Old spores are pale brown.
Anamorph
Pycnidia have not been found in the species.
Chemistry
The thallus does not react with C, K, KC, Pd or UV (C–, K–, KC–, Pd–, UV–), but the orange red pruina of the apothecia changes to purple in K (K+ purple). Pigments A1, A2 and A3 in variable amounts have been detected by TLC.
All parts of the apothecium react Idil+ red, I+ red and KI+ blue. A KI+ blue ring structure is present in the tholus of the asci. The orange, red and purple crystals dissolve in K with a clear and fleeting purplish solution.
Ecology
Coniocarpon cuspidans is an oceanic species that usually grows on the smooth bark of trees and shrubs in natural to old-growth forests and woodlands including boreo-nemoral rainforests and Corylus avellana grooves. The species has been observed in Norway most often on common hazel (Corylus avellana), more rarely on European ash (Fraxinus excelsior), holly (Ilex aquifolium), and rowan (Sorbus aucuparia). Coniocarpon cinnabarinum is a rare species that can be locally abundant.
The main distribution area of C. cuspidans in Norway is Rogaland and Vestland. A few observations have been made on Hidra in Vest-Agder. The species has been found in various forest communities, including among others oceanic Pinus sylvestris dominated coastal forest, Corylus avellana groves, broad-leaved deciduous forest and Fraxinus excelsior-dominated wooded scree-slopes.
Distribution in Norway and the Nordic countries
In the Nordic Countries, C. cuspidans has only been found in Norway.
Global distribution
Coniocarpon cuspidans has been distinguished from C. fallax only recently. Outside Norway, the species is confirmed for Scotland. It’s further distribution in western Europe is unclear.
Similar species
Coniocarpon cuspidans is the only Coniocarpon species lacking a visible pruina on the apothecia. From poorly developed individuals of C. cinnabarinum and C. fallax, it can be separated most easily by the small, predominantly 3-septate spores with a size range of 15–20 × 6–9 μm. Arthonia stellaris lacks quinoid pigments and the clearly lirellate apothecia are thinner.
Several other species of Arthoniaceae in Norway contain reddish, K+ purple pigments in the apothecia. The spores in all of them are only 1-septate and the reddish pigment is diffusely distributed in the gelatinous matrix only and not crystalline as in the Coniocarpon species.
Literature
Cannon P, Ertz D, Frisch A, Aptroot A, Chambers S, Coppins BJ, Sanderson N, Simkin J and Wolseley P (2020). Arthoniales: Arthoniaceae. Revisions of British and Irish Lichens 1: 1–48.
Frisch A, Moen VS, Grube M and Bendiksby M (2020). Integrative taxonomy confirms three species of Coniocarpon (Arthoniaceae) in Norway. MycoKeys 62: 27–51.