References

For Physocarpus

Alexander, C. 2014. Physocarpus. In Flora of North America Editorial Committee. 2014. Flora of North America north of Mexico. Volume 9, Magnoliophyta: Picramniaceae to Rosaceae. Oxford Univ. Press, New York, NY. 713 pp. Google Scholar

Kalkman. 2004. In Kubitzki, K., ed. 2004. The families and genera of vascular plants. VI. Flowering plants – Dicotyledons – Celastrales, Oxalidales, Rosales, Cornales, Ericales. Springer, Berlin. 489 pp. Google Scholar

Robertson, K.R. 1974. The genera of Rosaceae in the southeastern United States. J. Arnold Arb. 55: 303-332, 344-401, 611-662. Google Scholar

Spencer, A., and L.P. Bruederle. 2020. The geography of follicle pubescence in the Physocarpus opulifolius (Rosaceae) complex. J. Torrey Bot. Soc. 147: 327-337. Google Scholar