Flora of North America species comparison

The name Gentiana alba Muhlenberg has often been applied to this species. Uncertainty had long persisted, first as to whether the name G. alba was validly published by G. H. E. Muhlenberg in 1813, then, after that publication had been deemed invalid, whether it was validated by T. Nuttall in 1818. A group of nomenclatural authorities considered this issue on behalf of this flora and concluded that neither of those publications of the name G. alba had been valid, and that G. flavida A. Gray was the earliest validly published name for this species (K. N. Gandhi, pers. comm.).

Outlying eastern populations of Gentiana flavida in North Carolina, Pennsylvania, and West Virginia are no longer extant, and the continued existence of other peripheral populations in isolated prairie remnants is precarious. Reports from Manitoba have been based on misidentified G. rubricaulis. A report from Maryland was based on the misreading of a label of a specimen actually from Indiana (studies for this flora).

In contrast to those of the other species of Gentiana in the flora area, with the exceptions of G. clausa and G. latidens, the calyx lobes of G. flavida spread widely, with keels like shelf brackets decurrent on the tube.

Morphological variation in Gentiana flavida should be given further study. According to J. T. Curtis (1959), plants of this species from the northern part of its range, as seen in the field, appear distinctly different in inflorescence form from plants native farther south.

In the tall-grass prairies, Gentiana flavida hybridizes with G. andrewsii, producing G. × pallidocyanea J. S. Pringle, and G. puberulenta, producing G. × curtisii J. S. Pringle. Reports of G. flavida with the corollas distally lilac have been based on plants derived from such hybridization, probably through backcrossing.

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

Plants of Gentiana sceptrum with ascending, narrowly lanceolate leaves conspicuously exceeded by the distal internodes have been called G. menziesii. Plants with spreading, elliptic to ovate, more closely spaced leaves have been called G. sceptrum var. cascadensis, although that variant might more appropriately be considered nomenclaturally typical. Studies for this flora have indicated that the extremes are connected by many intermediates, and that little correlation exists between leaf shape and geographic distribution, or between leaf shape and the other traits by which the segregates have been characterized, such as stature, erectness of stems, or numbers and sizes of flowers. Even within a relatively limited area, such as Vancouver Island, British Columbia, or Humboldt County, California, plants can be found with leaves ranging from narrowly lanceolate to widely elliptic.

Small plants with strongly decumbent stems, found at a few localities at or near the coast in California and southern Oregon, have been called Gentiana sceptrum var. humilis. Spathaceous calyces occasionally occur in these plants. Such plants are not recognized taxonomically here because larger plants approaching typical G. sceptrum have been found at the same localities or nearby, but they should be given further study.

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