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