A key to species in the genus Bipolaris
(1)	Conidia slightly echinulate	B. hadrotrichoides
	Conidia smooth or slightly verruculose	2
(2)	Conidia often or sometimes rostrate	3
	Conidia fusoid, ellipsoidal, obclavate, ellipsoidal obclavate or cylindrical	4
(3)	Conidia 10–11 μm at the widest part, 2–7-distoseptate	B. eragrostiellae
	Conidia 14–18 μm at the widest part, 7–10-distoseptate	B. gossypina
(4)	End cells sometimes swollen to produce a thin, globose vesicle where germ tubes originate	5
	Germ tubes originating from both or one end cells without forming a vesicle	6
(5)	Conidia hyaline when immature, turning olivaceous green, then brown or golden brown when mature, 40–80 × 12–18 μm	B. cynodontis
	Conidia pale brown to dark brown, 65–105 × 15–20 μm	B. leersiae
(6)	Conidia less than 100 μm long	7
	Conidia longer than 100 μm	8
(7)	Septa equal or less than 5	B. obclavata
	Septa usually more than 5	9
(8)	Conidia equal or greater than 150 μm	20
	Conidia less than 150 μm	21
(9)	Sexual morph produced on Sach’s agar medium + rice/wheat straw; conidia hyaline, pale brown or reddish brown	18
	Sexual morph not reported; conidia olivaceous brown to dark golden-brown, greyish brown or brown	10
(10)	Producing secondary conidiophores in culture	11
	Producing only primary conidiophores in culture	12
(11)	Conidiophores up to 750 μm long, 7–9-distoseptate	B. microstegii
	Conidiophores 690 μm or less, 3–7-distoseptate	B. cookei
(12)	Conidia up to 60 μm long	13
	Conidia 60 μm or longer	14
(13)	Conidia less or equal to 40 μm long	B. colocasiae
	Conidia longer than 40 μm	15
(14)	Conidiophores up to 300 μm long	16
	Conidiophores longer than 300 μm	B. salkadehensis
(15)	Conidia 35–50 × 10–14 μm, up to 6-distoseptate; causing leaf spots on Muhlenbergia wrightii	B. arizonica
	Conidia 50–60 × 13–15 μm, up to 7-distoseptate; on Euchlaenae mexicana	B. euchlaenae
(16)	Conidiophores branched, arranged in dense groups	B. eragrostidis
	Conidiophores arising singly or in small groups	17
(17)	Conidia 55–90 × 12–14 μm, usually curved, 5–9-distoseptate	B. sacchari
	Conidia 35–50 × 14–20 μm, usually straight, 4–7-septate	B. coffeana
(18)	Conidia concolorous	19
	In mature conidia end cells paler than the middle cells	B. bicolor
(19)	Conidia 65–90 μm long and 13–20 μm wide	B. chloridis
	Conidia 60–75 μm long and 14–16 μm wide	B. peregianensis
(20)	Conidia distinctly curved, often C-shaped, occasionally horseshoe-shaped, more than 250 μm long	B. pluriseptata
	Conidia straight or curved, less than 250 μm long	22
(21)	Conidia wider or equal to 21 μm	28
	Conidial length less than 21 μm	29
(22)	Conidia usually greater or equal to 20 μm wide	23
	Conidia less than 20 μm wide	B. salviniae
(23)	Conidiophores longer than 350 μm	24
	Conidiophores shorter than 350 μm	25
(24)	Reported on Poaceae	26
	Reported on non-poaceous hosts	27
(25)	Conidia 80–150 × 15–19 μm, pale brown to dark olivaceous brown; sexual morph can be formed on WA + wheat straw	B. microlaenae
	Conidiophores 70–120 × 18–22 μm, brown to dark brown; sexual morph not formed	B. triticicola
(26)	Conidia 68–108 × 14–20 μm, brown when mature	B. oryzae
	Conidia 90–140 × 16–20 μm, olivaceous green when mature	B. panici-miliacei
(27)	Conidia 100–150 μm long, 8–13-distoseptate	B. incurvata
	Conidia 65–150 μm long, 7–10-distoseptate	B. heliconiae
(28)	Conidia end cells usually paler than the middle cells	39
	Conidia end cells concolorous	40
(29)	Conidia reddish brown	30
	Conidia pale brown, olivaceous brown, golden brown	31
(30)	Conidia clavate to fusoid	B. clavata
	Conidia ellipsoid	B. zeicola
(31)	On Euphorbiaceae	B. euphorbiae
	On Poaceae	32
(32)	Conidial end cells paler than the middle cells	33
	Conidia concolorous	34
(33)	Conidiophores up to 300 μm long, conidia pale, mid olivaceous or golden olivaceous	35
	Conidiophores up to 150 μm long, yellowish brown to dark olivaceous brown	36
(34)	Conidiophores more than 350 μm long	B. maydis
	Conidiophores less than 350 μm long	37
(35)	Conidia ellipsoidal, obclavate, to obclavate-ellipsoidal	B. drechsleri
	Conidia fusoid to obclavate fusoid	46
(36)	Conidia 70–110 × 9.5–17.5 μm	B. poae-pratensis
	Conidia 40–108 × 13–18 μm	B. mediocris
(37)	Conidiophores verrucose	38
	Conidiophores smooth	B. setariae
(38)	Conidia 55–90 × 12–16 μm; sexual morph observed on Sach’s agar + rice/wheat straw	B. victoriae
	Conidia 65–100 × 14–18 μm	B. yamadae
(39)	On Costaceae; conidia 70–105 × 14–22 μm, 7–10-septate	B. costina
	On Poaceae; conidia (30–) 40–80 (–120) × 12–18(–21) μm, 6–12-septate	B. zeae
(40)	Conidial width greater than or equal to 25 μm	41
	Conidial width less than 25 μm	42
(41)	Conidiophores longer than or equal to 250 μm	43
	Conidiophores usually less than 250 μm long	B. musae-sapientium
(42)	On Hevea brasiliensis	B. heveae
	On Poaceae	44
(43)	On Croton sp.; conidia (51–)60–110(–138) × (14–)20–25(–32) μm	B. crotonis
	On Poaceae; conidia (31–)40–72(–100) × 15–25(–27) μm	B. sorokiniana
(44)	Conidia usually curved, rarely straight, (43–)70–105(–120) × (9–)14–22 μm	B. stenospila
	Conidia straight or curved	45
(45)	Conidia 80–190 × 15–22 μm, 8–16-distoseptate	B. urochloae
	Conidia (41–)60–110(–138) × (9–)13–19(–24) μm, 4–12-distoseptate	B. halepensis
(46)	4–9-distoseptate (mostly 8)	B. secalis
	8–13-distoseptate (mostly 10)	B. luttrellii