Melchior, H. in Engler, H.G.A. & Prantl, K.A.E. (December 1925), Violaceae. Die Naturlichen Pflanzenfamilien Edn. 2, 21: 360 [comb. nov.]

basionym: Ionidium epacroides C.A.Gardner legitimate

Gardner, C.A. (May 1931), Part III. Geraniaceae–Compositae. Enumeratio Plantarum Australiae Occidentalis: 84 [secondary reference]

nomenclatural synonym: Ionidium epacroides C.A.Gardner legitimate

Bennett, E.M. (14 November 1972), A revision of the Australian species of Hybanthus Jacquin (Violaceae). Nuytsia 1(3): 240, Fig. 8 (map) [secondary reference]

nomenclatural synonym: Ionidium epacroides C.A.Gardner legitimate

Adams, L.G. & George, A.S. in George, A.S. (ed.) (1982), Violaceae. Flora of Australia 8: 109, Map 120 [secondary reference]

nomenclatural synonym: Ionidium epacroides C.A.Gardner legitimate taxonomic synonym: Hybanthus floribundus var. minutifolia F.Muell. legitimate taxonomic synonym: Hybanthus bilobus C.A.Gardner legitimate

Green, J.W. (1985), Census of the Vascular Plants of Western Australia Edn. 2: 118 [secondary reference]

taxonomic synonym: Hybanthus bilobus C.A.Gardner legitimate

Council of Heads of Australasian Herbaria (2005), Australian Plant Census: - APC [secondary reference]

nomenclatural synonym: Ionidium epacroides C.A.Gardner legitimate taxonomic synonym: Hybanthus floribundus var. minutifolia F.Muell. legitimate taxonomic synonym: Hybanthus bilobus C.A.Gardner nom. inval., nom. nud. taxonomic synonym: Hybanthus bilobus C.A.Gardner legitimate

• APC Dist.: WA

Forster, P.I. (24 March 2021), Reinstatement of Pigea Ging., an earlier generic name for the spade flowers previously included in Afrohybanthus Flicker (Violaceae). Austrobaileya 11: 30 [nomenclatural synonym]

nomenclatural synonym of: Pigea epacroides (C.A.Gardner) P.I.Forst. legitimate

---