Placynthiella
Crustose lichens containing a trebouxioid alga; thallus areolate, granular or goniocystose, any goniocysts sometimes adhering into columnar or coralloid structures, usually dark brown or blackish, but shade forms may be light blue-green, medium brown, olive or grey; apothecia with a non-algal rim, usually black or dark brown, the rim formed of rounded cells each surrounded by dark brown pigment; hymenium formed of gnarled, branched (but scarcely anastomosing) paraphyses embedded in gel, the paraphysis tips often abruptly swollen and capped in a dark brown pigment sheath; hypothecium dark brown; asci clavate to narrowly clavate, thin walled, with a scarcely thickened tholus (apparent only early in development), IKI- or IKI+ pale blue; spores 8 per ascus, colourless, simple, elliptical or ovate, often with a single large oil droplet.
References: Tønsberg 1992; Ryan, Hertel & Lendemer 2004.
| 1a. | Thallus consisting of loosely consolidated granules or coralloid upgrowths, often pale colours (gray, yellow-brown, pale green) or brownish black; apothecia uncommon or rare, medium to dark reddish brown …2 |
| 2a. | Thallus of isidiate upgrowths 25-200 µ high and 25-50 µ wide, pale green to medium or dark brown, rarely blackish; spores 8-12 × 4-5 µ …Placynthiella icmalea |
| 2b. | Thallus of soredioid granules 15-30 µ wide, mostly clustered in tight groups 25-50 (‑65) µ wide, pale green, bluish-gray, darkening to medium grey-brown on exposed granules; spores 9-14 × 4.5-6 µ (measured from one collection) …Placynthiella dasaea |
| 1b. | Thallus smooth, areolate, or of tightly consolidated granules, always dark brown to brownish black; apothecia usually present, dark brown to black …3 |
| 3a. | Thallus of areoles or granules 0.08-0.35 mm wide, medium to dark brown; apothecia 0.2-0.5 (‑0.8) mm wide; spores 10-14 (‑16) × 4.5-6 (‑7) µ; uncommon …Placynthiella oligotropha |
| 3b. | Thallus smooth to granular, any granules 0.025-0.12 (‑0.2) mm wide, dark brown to black; apothecia 0.1-0.3 (‑0.4) mm wide; commonly epiphytic; spores 9-14 (18) × (4‑) 5-6 (‑9) µ; common …Placynthiella uliginosa |
Placynthiella dasaea (Stirton) Tønsberg
Thallus formed of loosely attached weakly corticate granules and soredia, distinct soralia lacking, pale green, reddish brown, or (rarely) blackish; soredia irregularly heaped, somewhat corticate, 20-30 µ wide, but mostly in tight clusters up to 65 µ wide; apothecia occasional, matte dark red-brown, 0.3-0.6 mm wide, with a thin but prominent and persistent rim, the disc remaining flat; spores 9-14 × 4.5-6 µ.
Reactions: Spot tests all negative.
Contents: Gyrophoric acid and minor amounts of lecanoric acid.
Habitat: On conifer logs and at the bases of trunks, always within the winter snowpack. All forested elevations.
Similar Species: Pale forms may resemble some forms of Pycnora sorophora, which is C+ strongly orange-red (rapidly fading), K+ yellow and PD+ orange, and has at least slight yellowish tones. The apothecia may resemble those of Catinaria atropurpurea, which has a smooth, not granular thallus.
Specimens: Björk 12900.
Local Status: Occasional
Notes: At least some of our material may not match typical P. dasaea from Europe, having larger, more firmly corticate thallus granules, in being frequently fertile with larger apothecia, and in having only minor amounts of gyrophoric acid.
Placynthiella icmalea (Ach.) Coppins & P. James
Thallus formed of loosely attached, weakly corticate granules, the granules 20-30 µ wide, tending to be conjoined into vertical piles 50-190 µ tall that may branch, blackish, dark or pale grey-green or dark reddish brown; apothecia uncommon, matte dark red-brown, 0.2-0.6 (‑0.9) mm wide, with a thin but pominent and persistent rim, the disc remaining flat; spores 8-12 × 4-5 µ.
Reactions: Spot tests all negative.
Contents: Gyrophoric acid and minor amounts of lecanoric and 5-O-methylhiascic acids.
Habitat: On conifer logs and bases of trunks, always within the winter snowpack. All forested elevations.
Similar Species: Some forms of Pycnora sorophora may appear similar, but reacts C+strongly orange-red (rapidly fading), K+ yellow and PD+ orange.
Specimens: Björk 11641, 13204.
Local Status: Occasional.
Notes: Our material tends to have granules that pile up into unbranched, conical masses.
Placynthiella oligotropha (J.R. Laundon) Coppins & P. James
Thallus of often tall, tightly fitting smooth, corticate warts or squamules 0.1-0.3 mm wide and high, dark chocolate-brown, lacking soredia; apothecia common, 0.2-0.5 mm wide, matte blackish brown, individually scattered or a few clustered, the rim thin and eventually receding, the disc flat to low-convex; rim non-algal, pigmented dark reddish brown throughout; hymenium 50-70 µ high, colourless to medium reddish brown; upper hymenium medium reddish brown, granular; hypothecium dark reddish brown; paraphyses about 1 µ wide, richly branched and anastomosed; asci thin-walled except for the thin tholus at the tip, IKI- or IKI+ pale blue; spores 8 per ascus, ovate or broadly elliptical, 10-14 × 4.5-6 µ.
Reactions: All spot tests negative.
Contents: No known lichen substances.
Habitat: On bark or wood, always within the winter snowpack. All forested elevations.
Similar Species: See notes under Placynthiella uliginosa.
Specimens: Björk 14309.
Local Status: Uncommon.
Placynthiella uliginosa (Schrader) Coppins & P. James
Thallus smooth and continuous, or granular, any granules partly fused to the crust and not readily detached, dark brown or (mostly) black; apothecia common, matte or somewhat glossy, black or blackish brown, 0.2-0.4 mm wide, with a thin but persistent rim, the disc remaining flat or becoming weakly convex; spores 9-14 × 5-6 µ.
Reactions: Spot tests all negative.
Contents: No known lichen substances.
Habitat: On soil and detritus, less often on bark or wood, always within the winter snowpack. All forested elevations.
Similar Species: Placynthiella oligotropha may be similar, but has chocolate brown areoles and squamules.
Specimens: Björk 9014.
Local Status: Common.
References: Purvis et al. (1992); Foucard (1992).
Notes: Our material apparently differs from typical, European P. ulignosa in having a darker thallus and larger, blackish apothecia.