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 Calicioids of Temperate Regions
0.01 (development)
Eric B. Peterson
 

Acolium

Several of the common Cyphelium that lack a yellow thallus have been transferred to this genus. 

Taxa covered (5):

Key to Species

Validation script believes all taxa are included in the key(s).


  1. 1a. Parasitic on Pertusaria (usually causing some color alteration of the thallus and partial suppression of isidia or soredia); ascomata < 1mm diameter; spores predominantly ≤ 15 μm long.
    1. 2a. Ascospores 10-15 μm, spirally ornamented when young but becoming irregularly cracked (usually retaining some visibility of the initial spiral pattern).Acolium sessile
    2. 2b. Spores 11-13 μm and with less distinctive ornamentation. Known only from the British Isles and southwestern Europe.Acolium marcianum
  2. 1b. Not paracitic (no indication that the thallus does not belong to the ascomata); ascomata usually (but not always) > 1 mm diameter; spore size variable.
    1. 3a. Spores small, 7-10 (12) μm. Typically with a faint yellowish pruina on the rim.Acolium chloroconium
    2. 3b. Spores larger, excipular rim with a white to grey pruina.
      1. 4a. Ascomata 0.7-2mm in diameter. Thallus development quite variable from sparse, thin verrucae to thick and continuous; thallus color white to grey to greenish-grey. Spores 14-20 μm long and variable in ornamentation from smooth to faintly striate, to roughly cracked, but so thick and cracked as to become regularly distorted in outline. K+ reddish brown; P+ yellow. (This likely represents a group of morphologically indistinct species.).Acolium inquinans
      2. 4b. Ascomata mostly < 0.5 mm diameter. Thallus thin, verrucose, grey and becoming brownish with age in an herbarium. Spores 13 - 17 μm long with a very thick, deeply cracked ornamentation causing them to appear rough and somewhat distorted in outline. K- and P-.Acolium karelicum

Species Details

Acolium chloroconium Tuck.
ID=215
Type(s):
Synonyms:
Habit and Morphology:
Anatomy:
Chemistry:
Habitat:
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Conservation:
Notes:
External Information: References: Prieto & Wedin 2017.
Acolium inquinans (Sm.) A. Massal.
ID=216
Type(s):
Synonyms:

Cyphelium inquinans (Sm.) Trevis.

Lichen inquinans Sm.

Calicium tympanellum Ach.

Cyphelium tympanellum (Ach.) Ach.

 
Unspecified collections:
Spores of Acolium inquinans versus A. karelicum. Acolium inquinans spores have a rather thinly cracked or patchy spore ornamentation (A) if any cracking is visible at all. The spores of A. karelicum are distinctive in having an exceptionally thick spore wall with deep cracks (B).
Acolium inquinans. Humboldt County, California.
Acolium inquinans.
Acolium inquinans.

Habit and Morphology:

Lichenized with a trebouxioid photobiont.

Superficial and highly variable.  In the Pacific Northwest, this name is applied to specimens varying from brown to green to grey to almost white. Thallus texture varies from thin and almost smooth to verrucose and nearly areolate.  It is likely that multiple phylogenies are encompased in this variation.  Most published descriptions from other regions refer to grey, moderately verrucose forms.

Ascomata sessile to slightly immersed, typically greater than 1 mm diameter (up to ca. 1.5 mm).
Anatomy:

Ascospores 15 - 18 ?m long, broadly ellipsoidal. Tibell (1999) describes ornamentation as minute longitudinal ridges when young, becoming interrupted by a few irregular cracks at maturity.
Chemistry:
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Biogeography:
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Notes:
External Information: References: Prieto & Wedin 2017; Tibell 1969; Tibell 1999.
Acolium karelicum (Vain.) M. Prieto and Wedin
ID=217
Type(s):
Synonyms:
Unspecified collections:
Spores of Acolium inquinans versus A. karelicum. Acolium inquinans spores have a rather thinly cracked or patchy spore ornamentation (A) if any cracking is visible at all. The spores of A. karelicum are distinctive in having an exceptionally thick spore wall with deep cracks (B).

Habit and Morphology: Thallus grey to white. Ascomata sessile.
Anatomy: Excipular rim with a white pruina. Ascospores septate, with an exceptionally thick and deeply cracked wall.
Chemistry:
Habitat:
Biogeography: Known primarily from arid and semi-arid regions. In western North America, most specimens are from the northern intermountain west (between the Cascades and the Rocky Mountains).
Global Rank:
Conservation:
Notes: Acolium inquinans has quite variable spore ornamentation; specimens of A. inquinans with visible cracking are frequently mis-identified as A. karelicum.
External Information: References: Prieto & Wedin 2017.
Acolium marcianum (B. de Lesd.) M. Prieto and Wedin
ID=220
Type(s):
Synonyms:
Habit and Morphology: Parasitic on Pertusaria pseudocorallina. Ascomata sessile, 0.25 - 0.6 mm diameter, epruinose.
Anatomy: Ascospores 11-13 x 6-8 um. Ornamentation less distinct than A. sessile.
Chemistry:
Habitat:
Biogeography:
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Conservation: Considered very rare in the British Isles.
Notes: Considered valid by Prietin & Wedin (2017) although the only contemporary description of which I am aware is in Purvis at al. (1992).
External Information: References: Prieto & Wedin 2017; Purvis et al. 1992.
Acolium sessile (Pers.) Arnold
ID=223
Type(s):
Synonyms:
Acolium sessile. Arrows indicate patches of the Pertusaria thallus with some degree of isidia formation.
Acolium sessile ascospores. This example appears to have smaller spores than indicated in Tibell (1999), with some < 10 µm long.

Habit and Morphology: Parasitic on Pertusaria. The species parasitized are isidiate and although the parasitism suppresses formation of isidia, some are usually present at a short distance from any ascomata.
Anatomy: Ascospores 2 - 15 ?m long. Tibell (1999) describes the spore ornamentation as spirally ridged when young, becoming disrupted by irregular cracks at maturity.
Chemistry:
Habitat:
Biogeography:
Global Rank:
Conservation:
Notes:
External Information: References: Prieto & Wedin 2017; Tibell 1999.
Count of taxa = 5
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