AbstractAcaulonopsis, a new subgenus ofPhascum, has been erected to accommodate certain species exhibiting characters of bothAcaulonandPhascum.The taxa concerned are two new combinationsPhascum robustum(syn.Acaulon robustum)andPhascum robustumvar.crassinervium(syn.Acaulon crassinervium)and three new speciesP. laticostum, P. longipilumandP. readeranum.Descriptions and illustrations of each and of two other new taxa,Phascum tasmanicumvar.unguiculatuma new variety inPhascumsubgenusMicrobryumandPhascum beaugleholeia new species inPhascumsubgenusPhascumare provided as well as a key toAcaulonandPhascumin Australia.