Cyanothamnus penicillatus is a spreading shrub that grows to a height of 30 cm (10 in). The leaves are sessile and pinnate with three or five leaflets, each leaflet linear to narrow wedge-shaped and 5–12 mm (0.2–0.5 in) long. The flowers are borne singly in leaf axils on a pedicel 1–2 mm (0.04–0.08 in) long. The four sepals are egg-shaped, 1.5–2 mm (0.059–0.079 in) long and the four petals are white and 2–3.5 mm (0.079–0.14 in) long. The eight stamens are slightly hairy and there is a very short point on the end of the anthers. Flowering occurs mainly from October to November.[2][3]
^ abDuretto, Marco F.; Wilson, Paul G.; Ladiges, Pauline Y. "Boronia penicillata". Australian Biological Resources Study, Department of the Environment and Energy, Canberra. Retrieved 11 April 2019.
^Bentham, George; von Mueller, Ferdinand (1863). Flora Australiensis. Vol. 1. London: Lovell Reeve & Co. p. 322. Retrieved 11 April 2019.
^Duretto, Marco F.; Heslewood, Margaret M.; Bayly, Michael J. (2020). "Boronia (Rutaceae) is polyphyletic: Reinstating Cyanothamnus and the problems associated with inappropriately defined outgroups". Taxon. 69 (3): 481–499. doi:10.1002/tax.12242. S2CID225836058.
^Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. p. 173.