Spore examination is necessary to identify any of our black earth tongues to species. One can usually distinguish the two genera via examination of the fruiting bodies with a hand lens. Without careful examination, they are best placed here as Geoglossum/Trichoglossum species. Sometimes a crisp photo may reveal hairiness (Trichoglossum) or there may be instances in which one can see pieces of detritus stuck to the stalk or head, which would be a pretty good indication of the sticky Geoglossum. (J. Solem, pers. comm.)

Geoglossum: Smooth to finely pubescent, usually sticky to glutinous.
Trichoglossum: Velvety, usually dry.