Hawkeswood, T.J. (24 October 1984), Nine new species of Calothamnus Labill. (Myrtaceae: Leptospermoideae) from Western Australia. Nuytsia 5(1): 137-139, Figs 9, 18 (map) [tax. nov.]

• Type: "Murchison River, septentrionalem versus ad 424 m.p., (26°33′S, 114°30′E); ... 30 October 1963, F. Lullfitz 2842 (holo: PERTH)."

• Etymology: "Rigidus, Latin, meaning 'hard' or 'stiff', refers to the somewhat more rigid leaves possesed by this subspecies in comparison with the subspecies formosus."

Paczkowska, G. & Chapman, A.R. (2000), The Western Australian Flora, a descriptive catalogue: 350 [secondary reference]

Council of Heads of Australasian Herbaria (2010), Australian Plant Census: - [taxonomic synonym]

taxonomic synonym of: Calothamnus formosus Hawkeswood legitimate

Council of Heads of Australasian Herbaria (31 July 2018), Australian Plant Census: - [taxonomic synonym]

taxonomic synonym of: Calothamnus formosus Hawkeswood legitimate

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