Thomas studied at University College London, largely as a research apprentice to Ethel Sargant, receiving her BSc in 1905.
When Bedford College moved to Regent's Park in 1913, Thomas designed the botany garden and started plans for a plant physiology laboratory.
[2] After retirement, Thomas carried on her research from rooms in Westfield College, but stopped in 1940 due to poor health.
[1][2] Thomas is noted for investigations on flowering plants and was the first person in Britain to publish information about their double fertilisation.
She also worked extensively on her theory about double leaf-trace by studying both flowering and non-flowering seed producing plants.