1.	Sporangia sometimes with neck-like base	Umbelopsis longicollis
–	Sporangia without neck-like base	2
2.	Colonies drab grey when the sporangia are produced heavily	3
–	Colonies roseate to almost white when the sporangia are produced heavily	4
3.	Sporangia obovate to ovate	U. ovata
–	Sporangia globose to subglobose	U. isabellina
4.	With two kinds of sporangia, single- and multi-spored	U. dimorpha
–	With one kind of sporangia, single- or multi-spored	5
5.	Colony color white to pale pinkish; sporangia single-spored with 4.5–8.0 µm in diam.; sporangiospores globose with the same size of sporangia	U. nana
–	Colony color roseate to pale pinkish; sporangia multi-spored larger than 10 µm; sporangiospore globose to oblong-ellipsoidal far smaller than sporangia	6
6.	Sporangiospores globose, maximum growth temperature 40 °C	U. autotrophica
–	Sporangiospores subglobose, ovoid to oblong-ellipsoidal, angular or irregular; maximum growth temperature no more than 39 °C	7
7.	Sporangiophores no more than 100 µm in length	8
–	Sporangiophores mainly more than 100 µm in length	10
8.	Colonies reaching 20–21 mm in diam. on MEA after 7 days at 20 °C; sporangiospores globose, ellipsoidal or angular	U. sinsidoensis
–	Colonies reaching more than 30 mm in diam. on MEA after 7 days at 20 °C; sporangiospores angular	9
9.	Colonies russet; sporangiophores umbellately branched from distinct vesicles on agar surface, (16–) 23–63 (−80) µm in length; columellae small but distinct 3.2–5.5 × 1.6–3.8; without micro-chlamydospores	U. changbaiensis
–	Colonies light russet-vinaceous pinkish; sporangiophores simply branched from slightly swollen stalks, (27.7–) 47.4–94.8 µm in length; columellae absent or slightly convex up to 1 µm diam.; with micro-chlamydospores	U. vinacea
10.	Sporangia fusiform; without columella	U. fusiformis
–	Sporangia globose to subglobose; with distinct columellae	11
11.	Columellae distinct to inconspicuous and variable in shape and size; sporangiospores variable in shape and size up to 3.5–5 × 5–11 µm	U. heterosporus
–	Columellae distinct and uniform; sporangiospores mostly uniform and no more than 6 µm in diam	12
12.	Sporangiophores mainly umbellately branched from swollen portion of the subtended stalk	U. wiegerinckiae
–	Sporangiophores sympodial branched from slightly swollen stalks	13
13.	Sporangiospores angular	U. angularis
–	Sporangiospores not angular	14
14.	Sporangiospores with appendage	15
–	Sporangiospores smooth	17
15.	Sporangiophores straight, sporangiospores without a narrowed end, walls thickened unilaterally	U. gibberispora
–	Sporangiophores sometimes recurved; sporangiospores with a narrowed end, walls thickened or not	19
16.	Sporangiospores tear-shaped with 4.0–6.0 ×2.0–2.5 µm	U. swartii
–	Sporangiospores oval to clavate with distinctively thickened wall at the narrower end with 4.0–6.0–8.0 × 2.5–3.5 µm	U. westeae
17.	Colony color deep roseate, Indian red to dark vinaceous-brown; sporangial walls slowly deliquescent	U. dura
–	Colony color roseate to pinkish, brownish vinaceous to light russet-vinaceous; sporangial walls quickly deliquescent	18
18.	Sporangiospores ovoid to ellipsoidal no curved, mostly 2.4–3.5 µm in length	19
–	Sporangiospores ellipsoidal to oblong-ellipsoidal and sometimes slightly curved to one side, mainly 3.5–4.9 µm in length	20
19.	Colony diam. on CMA reaching 35–40 mm in diam. after 10 days at 18 °C; maximum growth temperature 31–32 °C; columellae mostly depressed globose (3.0–) 4.0–6.5 (–10.0) × (2.5–) 3.5–5.5 (–9.0) µm	U. microsporangia
–	Colony diam. on CMA reaching 40–44 mm in diam. after 10 days at 18 °C, maximum growth temperature higher than 32 °C; columellae mostly subglobose (4.0–) 6.0–8.0 (–10.0) µm	U. ramanniana
20.	Colony diam. on CMA reaching 60–62 mm in diam. after 10 days at 18 °C; colonies 1 mm in high; sporangiophores(120–) 270–475 (–980) µm in length	U. oblongielliptica
–	Colony diam. on CMA reaching 43–48 mm in diam. after 10 days at 18 °C; colonies up to 2 or 3 mm; sporangiophores commonly more than 500 µm in length	21
21.	Sporangiospores oblong-ellipsoidal to ellipsoidal, (3.6–) 4.0–4.9 (–5.5) × (1.7–) 2.4–2.8 (–3.2) µm; macro-chlamydospore not formed on CMA and MEA	U. macrospora
–	Sporangiospores ellipsoidal (2.7–) 3.2–4.5 (–5.7) × (1.6–) 2.0–2.4 (–2.8) µm in size; macro-chlamydospore abundant on CMA and MEA	U. curvata