Sclerotinia, Fuckel, 1870

Beatrice Senn-Irlet & Martina Peter, 2016, Sclerotinia cirsii-spinosissimi, a new species from the Alps, Ascomycete. org 8 (5), pp. 235-240 : 240

Key of Sclerotinia species from arctic-alpine habitats

1a Asci with four ascospores ......................................................................................................................................................................................................... 2

1b Asci with eight ascospores ....................................................................................................................................................................................................... 3

2a Ascospores 22–27 × 8–10 Μm; on leaf base of Ranunculus glacialis , fruiting shortly after snow melting ............................................................................................................................................................................................. S. glacialis F. Graf & T. Schumach.

2b Ascospores 10–15 × 5.6–8 Μm, on previous year stems of Rubus chamaemorus ............... S. tetraspora Holst-Jensen & T. Schumach.

3a Ascospores in size dimorphic, (10) 12–18 × 6–10 Μm including small spores; frequently on leguminous hosts, fruiting in summer in alpine environments ........................................................................................................................................................................ S. trifoliorum Erikss .

3b Ascospores not dimorphic ....................................................................................................................................................................................................... 4

4a Ascospores 14–21 × 6–9 Μm, subfusiform; on a variety of hosts, most frequently on Poa and Festuca (Poaceae) ......................................................................................................................................................................................................... S. borealis Bubak & Vleugel

4b Ascospores elliptic, oval, not subfusiform ........................................................................................................................................................................... 5

5a Ectal excipulum at margin of apothecium composed of globose cells, asci arising from croziers, ascospores 8–17 (–20) × 5–7 (9) Μm, with four nuclei, apothecia arising singly from each sclerotium .................................................................................... S. minor Jagger

5b Ectal excipulum at margin of apothecium composed of prosenchymatic cells oriented perpendicular to the apothecial surface, asci with or without croziers, ascospores with 2(–4) nuclei, apothecia arising singly or multiply from a sclerotium ............................. 6

6a Ascospores up to 5 Μm wide, asci without croziers, ascospores 9.2–11.7 × 3.8–5.0 Μm, medullary excipulum 150–300 Μm thick; sclerotia in axenic culture 0.6–4 mm diam.; on various dicots ......................................................................................................... S. nivalis Saito

6b Ascospores up to 7 Μm wide, asci with croziers, sclerotia in axenic culture 2–15 (–30) mm diam. apothecia 2–12 mm diam. .......... 7

7a Ascospores 9–13.5 (–15) × 4–6.5 (–7) Μm, mean Q> 2, with usually 2 small (ca 1 Μm diam) lipid bodies, with two nuclei, medullary excipulum 150–700 Μm thick, faintly to distinctly blueing in IKI; sclerotia in the soil without evident connection to the host plant, small to large, 4–25 × 2–10 mm, various host plants............................................................................................... S. sclerotiorum (Lib.) De Bary

7b Ascospores 9.5–12 × 5–6.5 Μm, mean Q <2, without lipid bodies, with 2(–4?) nuclei, sclerotia on and within host plant bracts, small, 4–8 × 1.5–4 mm, warty, medullary excipulum 40–250 Μm thick, not blueing in IKI, on Cirsium spinosissimum .................................................................................................................................................................................................................. S. cirsii-spinosissimi