His work consisted of studies in the fields of floristics, phytogeography and plant systematics, of which he conducted systematic investigations of ferns and also plants from the genera Verbascum, Rubus, Salix, Rumex, Mentha, Rosa, Carex and Epilobium.
Ferdinand Paul Wirtgen (1848–1924), German pharmacist and botanist; son of Philipp Wilhelm Wirtgen
Pope John Paul II | Paul McCartney | Paul Simon | Paul Newman | Pope Paul VI | St Paul's Cathedral | Paul | Jean-Paul Sartre | Peter Paul Rubens | Paul Robeson | Paul Anka | St. Paul | Ferdinand Marcos | Paul Hindemith | Paul Revere | Paul Weller | Paul Klee | Saint Paul | Paul Kelly | Paul Cézanne | John Paul Jones | Paul Ryan | Ferdinand Magellan | Paul Gauguin | Franz Ferdinand | Paul Oakenfold | Jean Paul Gaultier | Paul the Apostle | Paul Keating | Paul Auster |
Philipp Wilhelm Wirtgen (1806–1870), German botanist and teacher; father of Ferdinand Paul Wirtgen