From Williams et al., 2017:

[Micrhystridium, Deflandre, 1937b, p.79; Emendations: Staplin, 1961, p. 408; Sarjeant, 1967c, p. 204; Lister, 1970, p. 77; Sarjeant and Stancliffe, 1994, p. 12.
Acritarch genus.

For synonymy see Fensome et al., 1990.

Type species: Micrhystridium inconspicuum, Deflandre, 1937b (pl.12 (al. pl.9), fig.11)]