In 1947 Molesworth Allen received a scholarship to study in Basel, Switzerland. Stopping over in Malaya, she met and married Geoffrey Allen; declining the scholarship in Switzerland, she instead settled in Malaya where she trained in tropical botany and worked in the Singapore Botanic Gardens. From 1948 she travelled extensively in Southeast Asia, particularly to Malaysia, Borneo and Thailand, observing plants and collecting samples from the jungles. However, her work became dangerous during the 1948–1960 State of Emergency as Communist guerillas set up camps in the jungles.