Family Hydrastidaceae

Hydrastidaceae Lemesle

~ Ranunculaceae

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

Leaf anatomy. Stomata present; anomocytic.

Stem anatomy. Primary vascular tissue in scattered bundles. Medullary bundles present. Secondary thickening absent. Sieve-tube plastids S-type.

Reproductive type, pollination. Fertile flowers hermaphrodite. 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, biochemistry. Not cyanogenic.

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 3 core angiosperms; peripheral eudicot; Superorder Ranunculanae; Order Ranunculales (as a synonym of Ranunculaceae).

Species 2. Genera 1; only genus, Hydrastis.