Helicoon (Index Fungorum, 2018)

Goh, Teik-Khiang & Kuo, Chang-Hsin, 2018, A new species of Helicoön from Taiwan, Phytotaxa 346 (2), pp. 141-156 : 148-149

Key to 18 accepted species of Helicoön

1. Direction of conidial coiling clockwise.............................................................................................................................................2.

1. Direction of conidial coiling counter-clockwise...............................................................................................................................6.

2. Conidia fuscous.................................................................................................................................................................................3.

2. Conidia hyaline or pale......................................................................................................................................................................5.

3. Conidia large (78−120 μm × 48−90 μm), coiled 12−13 times................................................................................ H. gigantisporum

3. Conidia smaller (up to 78 μm), coiled up to 9 times........................................................................................................................ 4.

4. Conidia subglobose; conidial filaments 7.5−9.5 μm wide, coiled 8−9 times ........................................................... H. subglobosum

4. Conidia doliiform; conidial filaments 10−17 μm wide, coiled 4−7 times ..................................................................... H. doliiforme

5. Conidial filaments 8−10 μm wide, coiled 9−14 times, closely multiseptate ........................................................... H. septatissimum

5. Conidial filaments 5−8 μm wide, coiled 2−5 times, distinctly guttulate ............................................................. H. peruamazonense

6. Conidia hyaline, in mass white or yellowish.....................................................................................................................................7.

6. Conidia fuscous to dark brown, in mass some shade of brown to black.........................................................................................10.

7. Conidia larger (33−59 μm long), ellipsoidal or elongated................................................................................................................8.

7. Conidia smaller (15−37 μm long), oval or subglobose.....................................................................................................................9.

8. Conidia in mass yellow; conidial filaments 2.5−3.6 μm wide, hygroscopic..................................................................... H. auratum

8. Conidia in mass white; conidial filaments 4.5−6.5 μm wide, non-hygroscopic .................................................................. H. sessile

9. Conidia 15−17 × 16−20 μm; conidial filaments coiled 4−5 times............................................................................. H. microsporum

9. Conidia 22−37 × 20−27 μm; conidial filaments coiled 5−8 times.................................................................................. H. farinosum

10. Conidial filaments at least 6 μm wide.............................................................................................................................................11.

10. Conidial filaments up to 6 μm wide................................................................................................................................................13.

11. Conidia large (75−110 × 39−60 μm), borne on long (up to 200 μm) conidiophores that appear zig-zag at the apex ......................... ................................................................................................................................................................................... H. macrosporum

11. Conidia smaller and conidiophores not as above; colonies on natural substratum with abundant aerial mycelium comprising verrucose hyphae.............................................................................................................................................................................12.

12. Conidia 40−50 × 38−43 μm, loosely coiled 6−7 times ............................................................................................... H. maioricense

12. Conidia 50−87 × 50−62 μm, tightly coiled 8−10 times ..................................................................................................... H. richonis

13. Conidial filaments coiled 6−12 times..............................................................................................................................................14.

13. Conidial filaments coiled 4−6 times................................................................................................................................................16.

14. Conidia fuscous; conidiophores conspicuous, thick-walled, erect, up to 200 μm long, simple or sparingly branched....................... ................................................................................................................................................................................... H. fuscosporum

14. Conidia pale; conidiophores much branched..................................................................................................................................15.

15. Conidia doliiform, 30−38 × 17.5−21 μm, filaments 2.5−3.7 μm wide, coiled 9−11 times .......................................... H. dendroides

15. Conidia ellipsoidal, 28−45 × 18−32 μm, filaments 3−5.5 μm wide, coiled 6−12 times................................................. H. ellipticum

16. Conidia tangerine-shaped, 23−30 × 31−45 μm, filaments 5−6 μm wide, with 10−18 septa per coil....................... H. pluriseptatum

16. Conidia other shapes; smaller (up to 18 μm in length)...................................................................................................................17.

17. Conidia subglobose, fuscous, 15−18 × 14−17 μm, filaments 3−4 μm wide; produces abundant chlamydospores in culture which form sclerotium-like bodies................................................................................................................................. H. chlamydosporum

17. Conidia cup-shaped, pale to fuscous, ca. 15 × 25−28 μm, filaments 3.7−5.5 μm wide, gradually tapering toward the distal end..... ..................................................................................................................................................................................... H. myosuroides