15. Gillenia Moench (Indian physic)

Plants perennial herbs, with woody rhizomes. Stems erect or ascending, lacking spines and thorns, glabrous or hairy. Leaves alternate, sessile or with petioles less than 1 cm long. Stipules herbaceous, conspicuous or inconspicuous. Leaf blades broadly ovate to triangular in outline, mostly trifoliate, the uppermost sometimes simple, the leaflets sessile or nearly so, variously finely and sharply toothed to deeply lobed (toward the stem base), the upper surface glabrous or sparsely hairy, the undersurface sparsely to densely hairy. Inflorescences loose few-flowered panicles, terminal or sometimes also from the upper leaf axils, occasionally reduced to a single flower, with reduced leaflike bracts at the branch points. Flowers perigynous, slightly zygomorphic, the hypanthium deeply cup-shaped at flowering, persistent but tearing apart by fruiting, 10-nerved, usually dark red or purple, not subtended by bractlets. Sepals 5, 1–2 mm long, erect, triangular, with small peglike reddish purple glands and sometimes also short white hairs along the margins, persistent at fruiting. Petals 5, spreading to slightly drooping, linear to narrowly oblanceolate, white or pinkish-tinged. Stamens (10–)20, the anthers pink. Pistils 5 in a single whorl, appearing fused toward the base at flowering, but becoming separate by fruiting. Ovary superior, with 1 locule, with 2–4 ovules. Style 1 per pistil, erect, persistent at fruiting, the stigma minute. Fruits follicles, not hidden by the hypanthium, ascending, ovoid, somewhat curved toward the tip, dehiscing along the inner suture and also partially along the outer (dorsal) suture, with 2–4 seeds. Seeds 2.5–3.5 mm long, asymmetrically ovoid and somewhat angular, the surface usually finely wrinkled, reddish brown to dark brown. Two species, eastern U.S., Canada.

In many floristic manuals, the name Porteranthus Britton is used for this genus. Gillenia is the older of the two names, but is very similar in spelling to the unrelated Gillena Adans., a synonym of the non-Missouri genus Clethra (Clethraceae). Because the two spellings are so similar and Gillena was the earliest validly published name, many authors have considered Gillenia to represent a mere spelling variant and later homonym of Gillena (K. R. Robertson, 1974). Hunt (1982) officially proposed to conserve Gillenia (Rosaceae) against the little-used Gillena (Clethraceae), but his proposal was rejected by the Committee for Spermatophyta of the International Botanical Congress on the grounds that the two names do have different spellings, are not truly homonyms, and are not likely to be confused (Voss, 1986; Brummitt, 1988). Because of the language of this ruling, Gillenia must continue to be used as the oldest valid name for this genus.

In recent years, species of Gillenia have increased in popularity as garden ornamentals. The common names, Indian physic and American ipecac, refer to the medicinal use by Native Americans of a decoction of the rhizomes of both species for emetic purposes. Among other uses, they were applied externally to relieve symptoms of rheumatism (Moerman, 1998).