Flora of North America species comparison

Gentiana catesbaei is believed to be extirpated from New Jersey and Pennsylvania. Specimens from Alabama have been reidentified as G. saponaria as all such specimens seen in studies for this flora had the elliptic leaves and short calyx lobes typical of G. saponaria rather than the ovate leaves and much longer calyx lobes that characterize G. catesbaei.

From the more widely distributed Gentiana saponaria, G. catesbaei differs most conspicuously in its ovate rather than elliptic leaves, widest proximal to rather than near mid-length; calyx lobes widest near mid-length and usually 1.5–3 times as long as the tube; and generally with spreading rather than incurved corolla lobes.

Gentiana catesbaei is almost entirely restricted to the Atlantic coastal plain, where it displaces the closely related G. saponaria south of northeastern North Carolina. In the northern part of its range, where the ranges of these species overlap, they generally remain distinct, although a few plants apparently of hybrid origin have been found. A hybrid with the much less similar G. villosa is also known.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Genera ca. 100, species ca. 1800 (18 genera, 112 species in the flora).

In the tribal classification by L. Struwe et al. (2002), genera 1–7 in this flora are in tribe Chironieae Dumortier, subtribe Chironiinae G. Don. Species of Chironieae generally lack nectaries, although Sabatia reportedly has indistinct nectaries at the base of the ovary. Genera 8–17 are in tribe Gentianeae Dumortier. Gentiana, in which the nectaries are on the gynophore, is in subtribe Gentianinae G. Don; the remaining genera of the Gentianeae in the flora area, all of which have epipetalous nectaries, are in subtribe Swertiinae Grisebach. Voyria constitutes the monogeneric tribe Voyrieae Gilg, in which the nectaries (when present) are on the ovary or the gynophore.

Pedicel lengths given here refer to the true pedicels, between the most distal pair of bracts or bractlets and the calyx. In some genera, notably Centaurium, Sabatia, and Zeltnera, a flower terminating the ultimate branch of an inflorescence, directly subtended by bractlets, although sessile by this definition, may appear pedicellate. Corolla lengths as given are from the receptacle to the apices of the lobes (or plicae in Gentiana andrewsii).

The Gentianaceae include many species esteemed in ornamental horticulture. In addition to those noted under the respective genera, the more important species in North American horticulture include Exacum affine Balfour f. ex Regel, Persian-violet, native to the island of Socotra, Yemen, which is widely grown as a florists’ pot plant.

(Discussion copyrighted by Flora of North America; reprinted with permission.)