Eopyrenula
Crustose lichens or free-living fungi with trentepohlioid algae or lacking algae, sometimes with trebouxioid algae partly lichenized within; perithecia hemispheric to globose, blackish, with a colourless or pale brown exciple below an involucrellum; paraphyses (paraphysoids) loosely embedded in gel, simple or branched and sometimes anastomosing, periphyses also present, pointing downward into the perithecial chamber from around the ostiole; hymenium I+ yellowish or bluish; asci subcylindric, thin-walled throughout, IKI- or + light blue especially in the lower half; spores 2-8 per ascus, elliptical, light to medium brown at maturity, thin walled, with 3 or more septae, rarely 1-septate.
References: Harris 1973; Purvis et al. 1992.
Eopyrenula microtheca Björk ined.
Thallus a thin film, light green-gray when dry, translucent green when wet, containing an orange trentepohlioid alga and also clusters of trebouxioid algae; perithecia 0.1-0.15 mm wide, high-convex, scattered individually over the crust, the wall formed of rounded, dark brown-walled cells 4.5-5.5 µ wide, not incorporating bits of the substrate; K-; asci dense, narrowly elliptical, the paraphyses few; spores fusiform, with sharply pointed ends, pale to light brown, with 3-6 septae (most with 4 or 5), 17-20 × 4-5 µ; microconidia 1-celled, worm-shaped and curved, about 12 × 1.2 µ.
Reactions: All spot tests negative.
Contents: Unknown, but probably lacking known lichen substances.
Habitat: Growing over the cortex of an old polypore fungus on a fallen Betula papyrifera trunk in a low elevation forest
Similar Species: The arthopyrenioid peritheciate crusts all have spores with rounded cell ends and have perithecial walls formed of stringy hyphae usually incorporating bits of the substrate.
Specimens: Björk 14403.
Local Status: Rare.
Notes: All other Eopyrenula species have larger perithecia and spores that are larger, smaller, or with a different number of septae.