A botanist was a type of biologist who specialized in this branch of biological science was known as botany. A botanist who specialized in alien botany was called a xenobotanist.
For a while, Kamin's son Batai wanted to be a botanist. (TNG: "The Inner Light")
During the early 2260s, Leila Kalomi was the primary botanist of the Omicron colony on planet Omicron Ceti III. (TOS: "This Side of Paradise")
Kevin and Rishon Uxbridge were botanists who resided on the Rana IV colony. Kevin was a specialist in symbiotic plant life. (TNG: "The Survivors")
Miranda Vigo was trained as a botanist who, as Jean-Luc Picard recalled, "used to talk of running a farm." (TNG: "Bloodlines")
Keiko O'Brien practiced botany aboard the USS Enterprise-D, but temporarily gave it up, became a teacher on Deep Space 9. Initially, Keiko has misgivings about moving to Deep Space 9, stating "Starfleet doesn't need a botanist on this station," to which her husband reassured that "there's a whole new quadrant full of new plant life to explore." (DS9: "A Man Alone") On the contrary, Miles was known around his house as "the Black Thumb," explaining to Joseph, that "the only way I could get anything to grow was to marry a botanist." (DS9: "Paradise")
When Keiko later attended a conference, she asked Jadzia Dax to care for a plant from Ledonia III, which later became sick. Dax took the plant to Doctor Julian Bashir, who, upon studying it, proclaimed, "I'm a doctor, not a botanist." (DS9: "The Wire")
Keiko later took the position of chief botanist on a year long agrobiology expedition to the Janitza Mountains on Bajor. (DS9: "The House of Quark", "Fascination")
According to D'Vana Tendi, the hydroponics bay was to be "great for biomedical research, or just for flower fans." (LD: "Room for Growth")