The historically important Hedwig-Schwägrichen collection in G contains type material linked with the moss names of Johannes Hedwig. These originate from species that he described as new to science, or that were ascribed to him when his 1801 publication Species muscorum frondosorum was designated as the starting point for moss names (excepting Sphagnaceae). A small number of the Hedwig type specimens have not been found within the G holdings, amongst which was Ptychomitrium crispatum (Hedw.) A. Jaeger (Ptychomitriaceae). This species was newly described by Hedwig in his 1801 work, under the name Encalypta crispata Hedw., based on material from the Cape of Good Hope in South Africa that was collected by the Swedish naturalist Carl Peter Thunberg. The specimen used by Hedwig to describe this species was recently found in one of the original Hedwig herbarium storage cases, amongst a set of reference material that had not been accessioned into the herbarium. After more than two-hundred years in obscurity, the newly rediscovered holotype material of Ptychomitrium crispatum is discussed herein. A description and illustration of Ptychomitrium crispatum is given, based on the type and other material from South Africa.