Boris Aleksandrovich Keller was a Russian botanist born in St. Petersburg. He was the first director of the Komarov Botanical Institute.
After being expelled from Moscow University for his involvement in student politics, Keller continued his studies at Kazan University, graduating in 1902. He went on to teach at Kazan until 1913, when he was appointed professor at the Voronezh Agricultural Institute. He simultaneously worked at the University of Voronezh from 1919.

In 1931 Keller left Voronezh to take up directorship of the new Botanical Institute of the Russian Academy of Sciences (later known as the Komarov Institute). He also led the Academy's Soil Institute from 1935 and then transferred to the Moscow Botanical Gardens in 1937, where he remained until his death in 1945. In his last years he was also chair of the Turkmen branch of the Academy of Sciences.

Keller was known primarily as a geobotanist and focused his studies on the phytogeography and ecology of the Russian steppes, introducing classifications to differentiate types of steppe and steppe vegetation. He was also interested in feather grasses and plants able to tolerate drought and salt. One of his lasting legacies at the Komarov Institute was initiating the Flora of the S.S.S.R.

Sources:
D.V. Lebedev, 1979, "Keller, Boris Aleksandrovich", The Great Soviet Encyclopedia
S. Lipschitz, 1952, Russki Botaniki, 4: 127
S.G. Shetler, 1967, The Komarov Botanical Institute: 72-73, 143.