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.)

Reports of Gentiana parryi outside the range indicated here have been based on specimens of G. calycosa or G. affinis (studies for this flora). Because of its restriction to high altitudes, populations of G. parryi are widely scattered, especially in the southern part of its range.

Gentiana parryi has sometimes been included in G. calycosa and less often in G. affinis, but its larger, conduplicate involucral leaves, which are more or less sharply differentiated from the distal cauline leaves and largely envelop the calyces, give G. parryi an aspect distinctly different from that of either G. calycosa or G. affinis. Biometric studies by J. R. Spence (unpubl.) have supported its recognition as a species. As noted by N. H. Holmgren (1984b), these species also differ in anther length, which is 3.5–5 mm in G. parryi and 1.6–3.2 mm in G. calycosa and G. affinis. In the Rocky Mountains of central Colorado, G. parryi and G. affinis appear especially well differentiated. Where the ranges of G. parryi and G. calycosa approach each other in the Intermountain Region, G. parryi usually grows in drier habitats than G. calycosa. The distinctive involucre of G. parryi is less well developed in some Arizona plants otherwise identifiable as this species, which should be given further study.

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