These muri are usually closely packed but occasionally well spaced. The lips have crenulate outer margins. It is most common in the Ludfordian and latest Gorstian of the late Ludlow of the Upper Silurian. Synorisporites tripapillatus is smaller and has prominent interradial papillae. Synorisporites verrucatus is distally verrucate-murinate.
Spores belong to the plant kingdom.
Most palynologists agree that these forms represent ancient fruiting body elements of plants long extinct. This species of spore pictured was first discovered by Richardson and Lister in 1969.