A Review of the Classification of the Genus Hydrastis (Ranunculaceae)
The genus Hydrastis has been variously classified as a monotypic taxon in the Ranunculaceae, the Berberidaceae, the Glaucidiaceae, or its own monogeneric family, the Hydrastidaceae. The objectives of this paper were 1) to review the previous classifications of Hydrastis and 2) to critique a recent paper by Tobe and Keating reevaluating the classification of the genus based on comparative morphological and anatomical studies. One conclusion of this review was that Tobe and Keating overlooked certain important papers which might have substantially altered their conclusions, viz., that Hydrastis is sufficiently distinct from the other genera of the Ranunculaceae to warrant a classification as a monogeneric family. Another conclusion was that, with the present information available, Hydrastis can be classified as a subfamily within the Ranunculaceae, but that molecular data might well alter this conclusion.