[5] His wife Gertrud Dahlgren continued the work after his death.
[6] Dahlgren ranked the dicotyledons and monocotyledons as subclasses of the class of flowering plants (angiosperms) and further divided them into superorders.
Originally (1975) he used the suffix -anae, as did Cronquist, to designate these, but in 1980 changed this to -florae in accordance with Thorne.
In the 1989 revision, published by his wife, the alternate names Magnoliidae and Liliidae were dropped in favour of Dicotyledon and Monocotyledon, and the suffix -florae reverted to -anae (e.g. Alismatanae for Alismatiflorae).
[7] (Note the synonyms, both nomenclatural and taxonomic, for each name in the system.)