Gustav Heynhold was a German botanist who worked at the botanic gardens of Dresden and Frankfurt.
In 1828 he was in Trieste where he carried out mapping and published "Uebersicht der Vegetation in den Umgebungen Triest's; von Hrn. Gustav Heynhold zu Dresden." His best-known work was the Nomenclator Botanicus Hortensis, an index of the botanical names of garden plants. It is not certain whether he had an academic degree or title. In 1846 the "Botanischen Centralblatt für Deutschland" listed him as a private scholar in Dresden. In total he was responsible for naming some 426 plant species.
In 1841, he renamed Arabis thaliana as Arabidopsis thaliana Heynh. Arabidopsis was the first plant to have its genome sequenced, and is frequently used as a model for understanding the molecular biology of many plant traits, including flower development and light sensing.