Due to DNA testing there has been a recent lumping: Planchonella into Pouteria, Michelia into Magnolia, Rheeedia into Garcinia. This has been discussed and as i have stated (or have I?) taxonomy is a human invention. Its purpose is to identify plants. The fact that DNA shows no or minimal genetic difference is not or should not be the be all and end all. Why shouldn't after DNA we look at morphological differences? For example Magnolia has terminal flowers while Michelia has lateral.
I have been prompted to open this topic because of something that 'appauls' me. I was almost became a mycologist with a horticultural hobby. I recently found some Macrolepiota rhacodes (syn. Lepiota rhacodes) only to discover due to DNA it has now been lumped with Chlorphytum molybites.
Now I am convinced this new thrust to lump by DNA only is a nonsense.
Chlrorphtyum molybites is the ONLY genus and species with GREEN spores. Macrolepiota rhacodes has white spores like all other Macrolepiota and Lepiota species.
Spore coplur is the first port of call in identifying gilled fungi.