The genus Lissanthe R.Br. (Styphelioideae: Ericaceae) has been recently revised but further field and herbarium studies have brought to light two further species from southern Western Australia. Parsimony analysis of plastid atpB–rbcL spacer sequence data confirms the placement of these two species in Lissanthe. Thus, L. synandra Crayn & Hislop is described as new and L. pleurandroides (F.Muell.) Crayn & Hislop is transferred from Leucopogon. Lissanthe synandra is unique in the genus in having angled branchlets, corolla lobes that remain almost completely closed, and anthers that are fused and cohere around the style and stigma, forming a synandrium. Illustrations and distribution maps are provided for both species. A key to species of Lissanthe is included.