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.
Marsh or aquatic plants with radical or floating leaves, or rarely none, and irregular flowers on leafless radical or terminal peduncles. Corolla 2-lipped, projecting below into a spur or pouch. Stamens 2. Ovary and capsule 1-celled.
A family of very few genera, dispersed over the greater part of the globe.
Small insectivorous plants growing in bogs or on wet rocks, with radical, entire leaves, purple or yellowish flowers on leafless, radical peduncles. Corolla spurred, with a broad, open mouth. Capsule opening in 2 or 4 valves. Dead flies are frequently seen on the leaves.
Leaves in radical rosettes, lanceolate or obovate, obtuse, entire, with revolute margins, thick, glabrous, or covered with viscid glands. Stem erect, 1-flowered. Corolla pendent, creamy white with yellow spots on the central lobe and apex of the spur, which is gibbous.
Wet rocks and damp, stony pastures in Alpine and sub-alpine regions and in Switzerland, descending to turf-moors in the plain. May to July.
'Mountain ranges of Central Europe and Russian Asia. Arctic Europe and Asia. British.
Leaves similar to the last, but larger. Spur of corolla subulate, slender, about half length of corolla. Flowers violet, larger than in P. alpina.
Wet rocks and damp places, and especially in peaty meadows from the plains to about 6500 feet. May to July.
Europe and all round the Arctic Circle, Russian Asia, and North American. British.
Resembling the last, but larger in all its parts, with broader lobes and a longer spur to the corolla, and a more obtuse capsule. Throat generally white.
Damp meadows and peat bogs in the Alps and sub-Alps. May to August.
In Switzerland only in some of the Jura frontier peaks; Western Alps, Jura, Pyrenees, Corbieres, etc.; Ireland.
Probably a sub-species of the last. Upper lobes of calyx broader, obtuse. Corolla rose or lilac, with more or less violet throat. Spur very pointed. Transverse section of the capsule elliptic lozenge-shaped.
Damp sub-alpine meadows and pastures; rare. June to August.
Southern Jura, Haute-Savoie (Alps of Annecy, etc.). Maritime Alps.