Key to Danish species of Oligonema Rostaf.
| 1 | Spores finely warted. Elaters short with an indistict spiral ornamentation thickened apices. Spherical sporocarps. | O. fulvum Morgan |
| 1' | Spores win a net-ornamentation. Elaters with indistict warts or spiral bands. | 2 |
| 2 (1) | Sporocarps ± spherical, closely aggregated and often superimposed. Elaters with a faint spiral ornamentation. | O. schweinitzii (Berk.) G.W. Martin |
| 2' | Sporocarps higher than wide, in close groups but not superimposed. Elaters mostly with very fine, irregular warts. | O. flavidum (Peck) Peck |