German botanist who studied in Geneva, Switzerland (1842). He toured many countries studying their flora and made relevant studies and observations. He recorded species and catalogued hundreds of plants. He also came to Greece in 1851 and finally settled permanently, invited by Otto to create a botanical garden. This garden was created on a public estate (formerly Haseiki), next to the Iera Odos, covering an area of 120 acres.

From the researches of Heldreich 70 new plants were identified and registered in Greece which have his name in international botany and phytology. A large work with his records was published after his death by his colleague and technician Spyros Miliarakis and is entitled “Dictionary of the demotic names of plants”.

Heldreich published other special botanical studies that were translated internationally into 5 languages. He was co-founder of the Physiographic Museum of Greece with a Botanical, Zoological and Palaeontological Department. Part of his collection of plants of Greece is in the Natural History departments’ collection of the British Museum.

He was a member of the Council of the Grand Lodge of Greece.