Key E: Species occurring on Polytrichaceae

1 Ascomata obligately within the antheridial cups ........................................................................................................................................................................................................................................................ 2

1* Ascomata occupying other microniches ................................................................................................................................................................................................................................................................... 5

2 Ascomata apothecial, brown; asci unitunicate, iodine negative; ascospores nonseptate or 1-septate, 7.5 –9.5 × 3 μm (Helotiales) ........................................................................................................ Durella polytrichina

2* Ascomata perithecioid, black, forming a pseudostromatic plate-like structure; asci bitunicate; ascospores 1-septate, larger than 23 μm (Pleosporales) Lizonia ..............................................................………………........ 3

3 Asci 8-spored .......................................................................................................................................................................................................................................................................................................... 4

3* Asci 16-spored, 120 –150 × 18 –23 μm; ascospores 23 –29 × 7.5 –9.5 μm; on Oligotrichum aligerum, Polytrichum formosum .......................................................................….............................................. Lizonia baldinii

4 Asci 110 –160 × 19 –23 μm; ascospores 33 – 40 × 9 –12 μm; on Polytrichum commune, P. strictum ... ................................................................................................................................................... Lizonia emperigonia

4* Asci 90 –120 × 15 –20 μm; ascospores 23 –29 × 6 – 8.5 μm; on Polytrichastrum sexangulare ............ ................................................................................................................................................. Lizonia sexangularis

5 Ascomata completely immersed between the leaf lamellae (often distinctly erumpent in Bryonectria cuneifera) .............................................................................................................................................................. 6

5* Ascomata on the leaf lamellae or on the abaxial leaf surface ..........................................................................................................................................................................................................…………………..... 11

6 Ascomata perithecial, colorless; perithecial wall of thick-walled, irregular hyphae with delicate lumi- na; ascospores 1–septate, 10 –12.5 × 3.5 – 4.5 μm ...................................….............................. Bryonectria cuneifera

6* Ascomata perithecioid or lateral ascomatal walls strongly reduced or even absent due to lack of space, resulting in atypical ascomata with asci arranged in a row ....................................................................……......... 7

7 Ascomata perithecioid, globose (circular seen from above or elliptical in outline by lateral compres- sion), brown, to 55 μm diam, with or without setae .................................................................................................. 8

7* Ascomata seen from above fusiform and black or fusiform to linear and colorless, setae absent ................................................................................................................................................................................... 9

8 Setae to 20μm long; hymenial jelly reddish in iodine; ascospores 5.5–7 × 1.5–2μm; unspecific on species of Polytrichaceae ...............................................................................................……..... Epibryon interlamellare

8* Setae absent; inner ostiolar region reddish in iodine (bluish after pretreatment with KOH); ascospores 6.5 –9 × 2– 4 μm; common on Pogonatum urnigerum .................................................... Epibryon pogonati-urnigeri

9 Ascomata black with an irregular clear opening in transmitted light, in surface view 90–160μm long, 18 –55 μm wide; ascus walls reddish in iodine; ascospores 1-septate, 13 –16 × 2–2.5 μm; often associated with a black, fusiform or linear, also immersed pycnidial anamorph (Key H) ................................................................................................................................................................................………….............Potriphila navicularis

9* Ascomata colorless, excipulum extremely reduced, essentially a row of asci with some sterile cells at both ends and at the base; ascus walls not reddish in iodine ................................................................................. 10

10 Ascomata 20–50μm long, 8–14μm wide; asci 15–23 × 7–11μm, iodine reaction none; ascospores 1-septate, 6.5 – 8.5 × 2–2.5 μm ............................................................................................. Dawsomyces subinvisibilis

10*Ascomata 90–180μm long, 18–50μm wide; asci 55–85 × 11.5–18μm, with a blue apical ring in iodine; ascospores nonseptate, 13 –16 × 5.5 –7 μm; not rare on Polytrichastrum sexangulare ....... Gloeopeziza interlamellaris

11 Ascomata mostly on the abaxial leaf surface in the upper leaf region .............................................................................................................................................................................................................…....... 12

11*Ascomata on the leaf lamellae (arising from the interlamellar spaces).......…………………......................................................................................................................................................................................... 13

12 Ascomata 25 –50 μm diam; ascospores1-septate, 9 –11 × 3 – 4 μm; most often on Polytrichum piliferum .................................................................................................................…................... Bryochiton perpusillus

12* Ascomata 60 –110 μm diam; ascospores 2-septate, 11–14 × 3 – 4 μm; on Polytrichastrum sexangulare ............................................................................................................................…....... Bryochiton heliotropicus

13 Ascomata apothecial, green or brown ............................................................................................................................................................................................................................................................…..... 14

13*Ascomata perithecial or perithecioid, brown or black .....................................................................................................................................................................................................................................…..... 15

14 Apothecia green, to 120μm diam, margin dentate; ascospores 5.5–8 × 1.5–2μm; on species with free-lying lamellae not covered by the inflexed margins .................................................…........ Chlorociboria lamellicola

14* Apothecia pale brown, to 220 μm diam, without teeth; ascospores 8 –10.5 × 4 – 4.5 μm; on Polytrichum juniperinum, arising from the interstices of the lamellae where the inflexed leaf margins meet ....................................................................................................................................................................................................................................................................................……….. Bryoscyphus hyalotectus

364 Herzogia 36 (2), 2023

15 Perithecia brown; iodine reaction none; ascospores1-septate; arising from the interstices of the lamel- lae where the inflexed leaf margins meet, on Polytrichum juniperinum, P. piliferum .....…....... Bryonectria phyllogena

15*Ascomata perithecioid, black; hymenial structures including ascus apices reacting with iodine; asco- spores 3-septate, usually single or by twos in the uppermost leaf parts, on Polytrichastrum sexangulare ............................................................................................................................................................................................................................................................................................. Protothelenella polytrichi