Reinke had a keen interest in the systematics, developmental cycles, cytology and physiology of brown algae.
He has been credited for being the first to use the word soralia to refer to the propagule-producing area in lichens in an 1895 publication, introducing a term still in common use.
[5] Opposing the secularization of science, Reinke, along with his Lutheran friend Eberhard Dennert, founded the Keplerbund ("Kepler Association") in 1907.
They opposed Haeckel's Monist League, which aimed to "replace" German churches with the evolutionary theory as a secular religion,[6] and attempted to create a branch of popular science grounded in the Christian belief.
Reinke attempted to explain the process of biological change through a concept of morphogenesis and genetic regulation he referred to as the "Dominanten" theory.