Depending on which source one consults, the answer is either one (Asarum), or two (Asarum + Hexastylis). It is a classic lump-or-split situation. To mention just a few sources, Fernald (1950) and Gleason & Cronquist (1991) lump all the wild gingers into a single genus, whereas Radford et al. (1968), the Digital Atlas of the Virginia Flora (Virginia Botanical Associates 2010), and the Flora of North America (Whitmore & Gaddy 1997; Whitmore et al. 1997) split Asarum and Hexastylis apart. Deference to authority is a poor way to assess any scientific question, and for these wild gingers, the authorities are deeply split. To understand the case at hand, one needs to dig a little deeper.
Copyright © 2010, Virginia Native Plant Society. This article first appeared in Bulletin of the Virginia Native Plant Society: 29:2 (2010), 1, 5, 8.
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Hayden, W. John. "One Lump or Two: How Many Wild Gingers Inhabit North America?" Bulletin of the Virginia Native Plant Society 29, no. 2 (Spring 2010): 1, 5, 8.