Key to accepted Heteroconium species

1. Conidia dimorphic, one type of conidia is unicellular and concolorous and second type of conidia is bicellular and bicolorous...... ............................................................................................................................................................................................... H. simile

1. Conidia monomorphic, either concolorous or bicolorous ..................................................................................................................2

2. Conidia concolorous...........................................................................................................................................................................3

2. Conidia bicolorous..............................................................................................................................................................................4

3. Conidia hyaline to pale brown............................................................................................................................................................5

3. Conidia brown to dark brown.............................................................................................................................................................6

4. Conidia guttulated ................................................................................................................................................................. H. avilae

4. Conidia not guttulated ......................................................................................................................................................................17

5. Scar at both ends of conidia............................................................................................................................................. H. triticicola

5. No scars at the end of conidia.............................................................................................................................................................7

6. Conidia both euseptate and distoseptate………………………………………………..…...............................................................8

6. Conidia euseptate………………………………………………………………………....................................................................9

7. Occasionally with a secondary conidium, smooth-walled, 0–6-euseptate, 13–44 × 5.5–10 μm....................................... H. schimae

7. No secondary conidium observed, conidia 3–6-septate, 26–52 × 4–6 μm....................................................................... H. tropicale

8. Conidia aseptate to multi-septate, subclindrical to ellipsoid, verruculose, 10–60 × 7–8 μm....................................... H. kleinziense

8. Conidia 14–22-septate (6–8-euseptate, 8–14-distoseptate), straight or slightly curved, obclavate, 58–93.5 μm × 5–8 μm................ ....................................................................................................................................................................................... H. bannaense

9. Conidia single septate.......................................................................................................................................................................10

9. Conidia with more than one septa ....................................................................................................................................................11

10. Conidia fusiform to cylindrical, pale brown to reddish brown, 23–42.5 × 8.5–10.5 μm.................................................. H. indicum

10. Conidia obclavate to ellipsoid, brown, smooth, 12–24 × 4–6 μm................................................................................. H. ponapense

11. Conidia less than 7-septate ...............................................................................................................................................................12

11. Conidia more than 7-septate.............................................................................................................................................................15

12. Conidia at first smooth and hyaline, later verrucose. ................................................................................................... H. glutinosum

12. Conidia smooth-walled.....................................................................................................................................................................13

13. Conidia in chains of 2, 6–7-septate ............................................................................................................................ H. phellodendri

13. Conidia in chains of 3, less than 4-septate .......................................................................................................................................14

14. Conidia (1–)2-septate, 20–25 9 7–10 μm ......................................................................................................... H. tsoongiodendronis

14. Conidia 1–4-septate, 13.5–32.5 × 5.4–8.5 μm ................................................................................................................. H. lignicola

15. Conidia verrucose with longitudinal striations or with creases, 1–14-septate .............................................................. H. neriifoliae

15. Conidia smooth-walled, 1–10-septate .............................................................................................................................................. 16

16. Conidia not constricted at septa, cylindrical to fusiform, 35–95 × 8–12 μm ............................................................... H. arundicum

16. Conidia slightly constricted at septa, cylindrical to oblong, 10–40 × 3–7 μm.............................................................. H. citharexyli

17. Conidia with a double layered wall ................................................................................................................................. H. asiaticum

17. Conidia with a thick single layered wall ..........................................................................................................................................18

18. Conidia with apical cells pale brown.............................................................................................................................. H. annesleae

18. Apical and basal end of conidia pale brown.....................................................................................................................................19

19. With black band at each septum .......................................................................................................................................................20

19. Without black band at each septum ..................................................................................................................................................21

20. Conidia cylindrical or fusiform, 9–16-euseptate, brown, pale brown ends, 50–85 × 4–6 μm, in chains of 3 ..................................... ........................................................................................................................................................................................ H. neolitseae

20. Conidia, obclavate, thick-walled, 45–110 × 8–12 μm, 8–18-septate, in chains of 2................................................................. H. fici

21. Conidia blastocatenate, in chains up to 3, smooth, rarely verrucose, primary conidia 5–7-sepatate, truncate at both ends, 32–40(– 50) × 8–10 μm, secondary conidia 3–4 septate, rounded above and truncate below, 20–30 × 3–5 μm........................ H. decorosum

21. Conidia blastocatenate, in chains up to 4, smooth, obclavate, 4–7-septate, (mostly 6-septate), slightly constricted at septa, rounded at apex, truncate at base, 31–45 × 7.5–8.7 μm, 4–7-septate............................................................ Heteroconium tulsiense sp. nov.