Moss or Frémont’s or lone gentian

Herbs biennial or sometimes annual, 0.1–1.3 dm, glabrous. Stems 1–10(–25), decumbent to erect. Leaves basal and cauline, cauline leaves gradually smaller, more widely spaced and more strongly ascending distally; blade conspicuously white-margined, apex acute; basal blades widely spatulate to ovate or orbiculate, 0.2–1.3 cm × 1.5–8 mm; cauline blades oblanceolate to linear, distal blades 4–7 × 0.6–2 mm. Inflorescences solitary flowers. Flowers: calyx 4–12 mm, lobes narrowly oblong-triangular, 1.5–3.5 mm, margins not ciliate; corolla white to pale blue or rarely deeper blue, often with dark blue lines abaxially, nearly salverform, open, 7–15 mm, lobes lance-ovate, 2–4 mm, free portions of plicae low-triangular with margins entire or shallowly erose-serrate or notched at apex; anthers distinct. Seeds not winged.

Flowering (late spring–)summer. Subalpine wet meadows; 600–3700 m; Alta., Sask.; Ariz., Calif., Colo., Mont., Nev., N.Mex., Utah, Wyo., restricted to high ele­vations south of Saskatchewan.

In contrast to the deep green stems and leaves of Gentiana prostrata, the vegetative parts of G. fremontii are much paler. G. Engelmann (1879) described plants of G. fremontii as having a pale, sickly appearance, and J. A. Ewan annotated specimens as having been yellowish when seen in the field, reminiscent of a fungus or broomrape (Aphyllon or Orobanche). This suggests that mycorrhizal symbiosis is especially significant in this species, but its trophic ecology has not been studied.

Gentiana fremontii differs further from G. prostrata in having obovoid capsules less than twice as long as wide, generally not fully exserted from the marcescent corolla, narrowly winged distally along the sutures, with valves that eventually separate nearly to the base, whereas the capsules of G. prostrata are compressed-cylindric, more than twice as long as wide, often fully exserted at maturity, not winged, with the valves separating only above the middle. Also, although both species vary in this respect, G. fremontii more often has the flower parts in fives.

The names Gentiana aquatica Linnaeus and Chondrophylla aquatica (Linnaeus) W. A. Weber have often been applied to this species. Gentiana fremontii, although similar to the Siberian and Chinese G. aquatica, appears to differ consistently in the wider, more con­spicuous white margins of its leaves, longer and pro­portionately narrower mid-cauline leaves, usually white rather than blue corollas, and corolla plicae that gen­erally have jagged rather than entire summits. The illegit­imate name G. humilis Steven 1812, not Salisbury 1796, has also been applied to G. fremontii, but the North American plants are not now considered conspe­cific with the type from Azerbaijan.