A botanist who had loved Spock years earlier and who, under the influence of alien spores, briefly won his affection on Omicron Ceti III.
Leila Kalomi had known Spock on Earth some years before and loved him without return. She later joined the agricultural colony on Omicron Ceti III, where the colonists survived deadly radiation thanks to alien spores that also left them peaceful and content.
When the Enterprise arrives, Leila leads Spock to the plants, and under their influence he finally expresses his feelings for her. The spores soon spread through the entire crew. Kirk breaks their hold by provoking Spock into anger, and Leila is left heartbroken as the colony is evacuated. She was played by Jill Ireland.