My first collections were made in 1945 in Grangärde parish in the province of Dalarna, Sweden with Hugo Sjörs as mentor. In the years that followed, I made many specialised trips to collect both mosses and vascular plants, in Sweden and abroad. After 1953 my profession as a chemical engineer took me on long overseas journeys to exotic areas and I always took the opportunity, when it was possible, to collect bryophytes. After 1968, I have collected sporadically, mainly on vacation journeys in southern Europe.
During this period from 1968 to 1992, I had little time to examine and determine my collections but by the latter year, I had retired from my profession and was given a working place at NRM/KBO.
My most important collections come from Arjeplog parish, Pite lappmark, Sweden, situated on the Arctic Circle (1949 + 1960, 1286 specimens), the Mascarenes (1962, 1195 specimens), the Stockholm area (1707 specimens) and Tasmania (1966, 292 specimens). At present I am working with my collections from Canada (1964, Ontario and Québec)
My collections have resulted in a number of new species, of which some have been named after me, such as Fissidens eenii Bizot (1968) from Mauritius and Lepidozia eenii plus Plectocolea eenii, both S. Arnell and from Queensland, Australia. Furthermore, some earlier work of mine with yeast fungi resulted in a new genus, Eeniella (Smith, Maudy T. & Batenburg van der Vegte, Wilma H. & Scheffers, W.A. 1981. Eeniella, a New Yeast Genus of the Torulopsidales. International Journal of Systematic Bacteriology 31(2): 196-203)