This section is from the book "Sub-Alpine Plants Or Flowers Of The Swiss Woods And Meadows", by H. Stuart Thompson. Also available from Amazon: Sub-Alpine Plants: Or, Flowers of the Swiss Woods and Meadows.
Stem very short. Root-leaves in small rosettes, small, leathery, 1-nerved, a pair of lanceolate stem-leaves often immediately below the calyx. Calyx-lobes lanceolate, subacute, divided by a usually sharp sinus. Corolla deep blue with greenish streaks, rarely white or mauve, 1-1 1/2 inches long, lobes rather obtuse and short.
Grassy Alpine pastures up to 8500 feet, but not often seen in the sub-Alps, and much less common than G. excisa.
Alps, Jura, Pyrenees, Spain, N. Italy. In Switzerland in the southern ranges only.
On the type specimen of G. acaulis in the Linnaean herbarium Linnaeus wrote, "Gentiana caule unifloro flore campanulato caulem longitudine excedente".
Larger and taller than the last, with which Linnaeus combined it and the next to form G. acaulis L. Stem 2-4 inches high, erect, with a pair of small, lanceolate leaves lower in the stem; stem much elongated on maturity. Leaves larger and softer than in G. alpina, but very variable in shape and size. Calyx-lobes oval-lanceolate, from a narrow base, contracted, shorter and broader than in the last and spreading; sinus between calyx-lobes truncate, the membrane connecting the divisions of the calyx more developed. Corolla 1 1/2-2 1/2 inches long, campanulate, deep blue, spotted or streaked with green within and often of a duller or purplish blue, very rarely white or violet. Corolla-lobes large, toothed, and deflexed.
1 Perner et Songer, PL nouv. Savoie (1853), p. 53.
Pastures in the primitive or granitic Alps, less often on limestone. Often abundant from 3800-8500 feet.' May to August, according to position.
Eastern, Central, and Western Alps; Jura, Cevennes, Corbieres, Pyrenees, Central Europe; Carpathians.
The beautiful and very rare white variety drawn by Mr. Flemwell was found by him near the Hotel du Planet, above Argentiere. (Plate XXV).
Stem short, often almost wanting. Radical leaves coriaceous, stiff, lanceolate or elliptic-lanceolate, acute or acuminate. Stem-leaves much smaller, oval-lanceolate, sharply acuminate; uppermost stem-leaves rough at the edges. Corolla always peduncled (peduncles much elongated after maturity), azure-blue, not spotted or streaked with green. Calyx-lobes always very acute, not contracted at the base, about half length of calyx-tube; sinus usually acute.
Alpine pastures on limestone, and limestone rocks from 4000-8500 feet, lower in the Jura, and in Cantons Vaud and Zurich. May to July.
Carpathians, Eastern, Central, and Western Alps; Jura, Cevennes, Pyrenees, N. Spain, Central Italy, Dalmatia, Bosnia, Servia, Montenegro.
Sometimes this species and G. Kochiana seem to mutually exclude the other in their respective areas.