Flora of North America species comparison

Gentiana puberulenta is evidently extirpated from Ontario, Louisiana, Maryland, and New York, where outlying prairie communities have largely been eliminated by agricultural and urban expansion.

The name Gentiana puberula Michaux 1803, not Franchet 1890, and the homotypic synonym Dasystephana puberula (Michaux) Small have long and often been misapplied to this species but are typified by a specimen of G. saponaria.

Some small plants of Gentiana puberulenta appear similar to G. affinis var. affinis, but only a few specimens appear actually to be hybrids between these species. Where their ranges approach each other, the flowers of G. affinis are generally much smaller than those of G. puberulenta, and the corolla lobes of G. affinis are generally less than twice as long as the free portions of the plicae, whereas those of G. puberulenta are more than twice as long. The flower size of G. affinis var. ovata more closely approaches that of G. puberulenta, but in that variety, the range of which does not overlap that of G. puberulenta, the leaves are usually ovate to elliptic rather than narrowly oblong-lanceolate, and the distal internodes are often about as long as or longer than the leaves, in contrast to the proportionately shorter internodes of G. puberulenta. For further guidance in distinguishing between G. puberulenta and G. affinis, see discussion under 13. G. affinis.

Hybrids of Gentiana puberulenta with the strikingly dissimilar G. andrewsii, constituting G. × billingtonii Farwell (as species), and with G. flavida, constituting G. × curtisii J. S. Pringle, occur in the tall-grass prairies. Hybrids with G. saponaria formerly occurred in western Maryland.

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

In addition to the color forms noted in the description, a bicolored form of Gentiana calycosa in southwestern Washington has blue corollas with the center of the distal third of the corolla lobes, including the short-acuminate tip, white.

Gentiana calycosa varies greatly in stature and in the size of its leaves and flowers. Most plants of G. calycosa from the Pacific coastal region, including western Washington and Oregon and most of California, have tubular calyces with well-developed, ovate to elliptic lobes varying in size but usually 3–8 mm. In Canada such plants also prevail east to Alberta; southward, in the United States, they also prevail in Wyoming. From eastern Washington and Oregon to Idaho and parts of Montana, and in Nevada and Utah, the calyces are usually cleft and spathaceous, with the lobes much reduced, less than 3.5 mm, and linear, or vestigial or absent. Extreme forms of such plants have been called subsp. or var. asepala. Because of the sporadic rather than continuous distribution of such forms, the intergradation, especially in the vicinity of Mount Rainier, Washington, and in parts of Montana, where populations may include plants approaching both extremes along with intermediates, and the lack of correlation with other morphological variation, such plants are not distinguished taxonomically in this flora. To some extent their occurrence appears to be correlated with warmer, drier regions, and may be influenced by the habitat.

In most of its range, Gentiana calycosa grows in wet alpine meadows and similar moist habitats, but in the western Cascades it almost always grows in drier, north-facing sites on rocky slopes and cliffs. (T. Harvey, pers. comm.). Plants of G. calycosa in well-drained rocky slopes were distinguished as G. saxicola English (1934), not Grisebach (1838). According to C. S. English (1934), these plants differ from those of wet alpine meadows in having erect rather than decumbent stems; internodes mostly about as long as the leaves rather than distal internodes much longer than the leaves; and spreading rather than erect calyx lobes, which are larger and proportionately wider. According to Harvey, in contrast, the stems of the plants from the drier, rocky sites in the western Cascades are more likely to have decumbent stems. No consistent association of these morphological variations or correlation with geographic distribution was substantiated in the studies for this flora, but further study would be desirable, as molecular phylogenetic studies (A. Favre, pers. comm.) suggest that taxonomic recognition of these ecotypes might be appropriate.

There are records of hybrids of Gentiana calycosa with G. affinis var. affinis and G. newberryi var. newberryi.

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