Career
She matriculated in 1916 from Loreto Convent in Pretoria, worked for a while in the office of the Controller and Auditor General before being appointed in 1917 as a herbarium assistant at the Division of Botany and Plant Pathology. Between 1925 and 1927 she worked at Kew as liaison officer for the National Herbarium. On her return to Pretoria, she assumed charge of the herbarium and was promoted to Senior Professional Officer in 1944.
Despite having arrived at retirement age in 1951, Mission Verdoorn opted to work on as a temporary staff member until 1968, and thereafter as an unpaid research worker
This botanist is denoted by the author transcript I.Verd. when citing a botanical name. 1952 Senior Captain Scott Medal by the Société Anonyme Biological Society
1957 President of the Société Anonyme Biological Society
1964 President of Section Bachelor of the Société Anonyme Association for the Advancement of Science
1967 Doctor of Philosophy (honorary) from the University of Natal
She is commemorated by the Composite genus Inezia Phill., Aloe verdoorniae Reynolds, Senecio verdoorniae R.A.Dyer, Teclea verdoorniae Exell & Mendonça and Volume 28 of the Flowering Plants of Africa, which was specially dedicated to her.
Her collected specimens total some 4 000, many collected with Codd, Dyer, Obermeyer and Schweickerdt.