| # The Families of Angiosperms |

L. Watson and M.J. Dallwitz

### Hydrastidaceae Lemesle

~ Ranunculaceae-Hydrastidoideae.

Habit and leaf form. Herbs. Perennial; rhizomatous. Leaves simple. Lamina dissected; palmatifid. Leaves exstipulate.

Leaf anatomy. Stomata present; anomocytic.

Axial (stem, wood) anatomy. Primary vascular tissues consisting of scattered bundles. Medullary bundles present. Secondary thickening absent.

Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite. Floral nectaries absent.

Inflorescence, floral, fruit and seed morphology. Flowers solitary; small; partially acyclic, or acyclic. The androecium acyclic and the gynoecium acyclic. Free hypanthium absent. Hypogynous disk absent.

Perianth sepaline; 3; petaloid. Calyx 3 (of petaloid sepals); 1 whorled; polysepalous; not persistent (caducous).

Androecium 30–100 (‘many’). Androecial sequence determinable. Androecial members maturing centripetally; free of the perianth; free of one another. Androecium exclusively of fertile stamens. Stamens 30–100 (‘many’); polystemonous. Anthers non-versatile; dehiscing via longitudinal slits. Pollen grains aperturate; 3 aperturate.

Gynoecium 30–100 carpelled (‘many’). Carpels increased in number relative to the perianth. Gynoecium apocarpous; eu-apocarpous; superior. Carpel 2 ovuled. Ovules bitegmic.

Fruit fleshy; an aggregate. The fruiting carpels coalescing into a secondary syncarp (this bright red). The fruiting carpel indehiscent; drupaceous. Fruit (drupelet) 1 seeded. Seeds endospermic. Embryo achlorophyllous (1/1).

Physiology, phytochemistry. Not cyanogenic. Berberine present. Sieve-tube plastids S-type.

Geography, cytology. Temperate. One species in Japan, the other in Eastern North America. 2n = 26.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Ranunculiflorae (?); Ranunculales (?). Cronquist’s Subclass Magnoliidae; Ranunculales. APG III core angiosperms; peripheral eudicot; Superorder Ranunculanae. APG IV Order Ranunculales (as a synonym of Ranunculaceae).

Species 1 (Hydrastis canadensis). Genera 1; only genus, Hydrastis.

General remarks. This description is hopelessly inadequate, but differs from that of Ranunculaceae (q.v.). in the perianth of 3 petaloid sepals, the drupaceous, red fruiting carpels coalescing to form a syncarp, and (in so far as stem anatomy has been adequately sampled for the larger assemblage) the record of stems with medullary vascular bundles.

Illustrations. • Hydrastis canadensis: Köhler’s Medizinal-Pflanzen (1897). • Hydrastis canadensis (flowering): Bot Mag. 57 (1830). • Hydrastis canadensis (fruiting): Bot. Mag. 60 (1833).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 8th June 2026. delta-intkey.com’.

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