1	Giant cells known	2
–	Giant cells unknown	15
2	Aborted sporangia known	3
–	Aborted sporangia unknown	G.hydei
3	Fertile sporangia > 25 μm diameter	4
–	Fertile sporangia < 25 μm diameter	10
4	Sporangiospores mainly not reniform	5
–	Sporangiospores mainly reniform	7
5	Columellae mainly ellipsoidal	G.qichaensis
–	Columellae mainly not ellipsoidal	6
6	Fertile sporangia 14.2–27.1 μm	G.pingtangensis
–	Fertile sporangia, 13.0–41.0 μm	G.lacrispora
7	Sporangiospores > 4 μm wide	8
–	Sporangiospores < 4 μm wide	10
8	Sporangiophores branched ≥ 3 times	G.namwonensis
–	Sporangiophores branched < 3 times	9
9	Columellae mainly globose and subglobose, 4.0–8.0 μm	G.brasiliensis
–	Columellae mainly hemispherical, 1.8–4.7 × 2.0–7.7 μm	G.pamphilae
10	Apophyses mainly reniform, 2.8–3.5 × 1.8–2.3 μm	G.reniformis
–	Apophyses mainly reniform, 3.2–5.5 × 1.7–3.1 μm	G.apophysata
11	Sporangiophores branched > 3 times	12
–	Sporangiophores branched ≤ 3 times	14
12	Giant cells > 6 μm diameter	13
–	Giant cells < 6 μm diameter	G.abortosporangia
13	Columellae mainly subspherical and ovoid, 2.6–5.2 × 3.2–6.5 μm	G.oleae
–	Columellae mainly hemispherical, 4.4–5.6 × 8.5–9.0 μm	G.multiramosa
14	Apophyses oval, subglobose and gourd-shaped	G.bawanglingensis
–	Apophyses long fusiform, oval and egg-shaped	G.inconstans
15	Fertile sporangia > 25 μm diameter	16
–	Fertile sporangia < 25 μm diameter	17
16	Apophyses vasiform, 5.0–15.0 × 4.5–15.0 μm	G.pedratalhadensis
–	Apophyses ellipsoidal to subglobose, 4.5–8.5 × 4.5–6.0 μm	G.sichuanensis
17	Columellae hemispherical	18
–	Columellae not hemispherical	19
18	Apophyses urn-shaped to subglobose, 6.0–12.0 × 6.0–10.0 μm	G.chlamydospora
–	Apophyses oval, 7.0–10 × 8.0–8.7 μm	G.butleri
19	Sporangiospores ≥ 3.5 μm long	20
–	Sporangiospores < 3.5 μm long	21
20	Apophyses globose to subglobose, 3.5–6.5 × 3.0–7.0 μm	G.eborensis
–	Apophyses pyriform to subglobose, 8.0–12.0 × 7.0–9.5 μm	G.multispora
21	Sporangiospores ≥ 4 μm width, mostly not bean-shaped	22
–	Sporangiospores < 4 μm width, mostly bean-shaped	23
22	Columellae hemispherical, spherical or ovoid, 2.5–12.0 × 2.0–12.0 μm	G.guangdongensis
–	Columellae hemispherical and globose, 2.0–3.0 × 3.5–7.0 μm	G.zunyiensis
23	Sporangiospores 2.0–3.5 × 2.0–2.5 μm	G.orasabula
–	Sporangiospores 1.7–2.1 × 2.1–3.8 μm	G.koreana