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.
Very similar to the last in habit and shape of leaves, but the spikes are at first ovoid and then cylindrical. Stigmas 3. Stamens glabrous. Stem leafy in lower portion. Flowers dark blue. Pastures on siliceous soil up to 8000 feet. July, August.
1 The pale blue spike figured is probably P. spicatum.
Southern Germany, Southern Austria, Central and Western Alps; Pyrenees, Spain.
Stems 1-2 feet high, rather stout, usually glabrous, leafy below. Root-leaves longly petioled, ovate heart-shaped, crenate-dentate; upper leaves narrower, sessile, usually entire. Flowers dirty greenish white or pale blue, in an ovoid head which lengthens into a spike 2 inches or more in length.
Central and South-Central Europe, extending northwards into Britain (Sussex) and Norway.
Stem 6-18 inches high, erect, often hollow. Lower leaves lanceolate, with a truncate or almost cordate base, stalked, crenate-serrate; upper stem-leaves narrower, sessile. Involucral bracts lanceolate, somewhat serrate. Flowers deepest blue, or sometimes deep blue-violet, in globular heads an inch in diameter. Stigmas 3. Very variable in size.
Meadows and pastures from the plains to about 8600 feet; often very abundant, especially on limestone soil from 4000-5000 feet. June, July.
Central and Southern Europe, extending to the chalk downs of Southern England.
The tallest and stoutest species. Stem 2-3 feet high, thick, hollow, leafy at the top. Radical leaves with very long petioles, broadly heart-shaped, and irregularly or coarsely toothed; upper leaves sessile. Flowers dark violet, in dense oblong-cylindric heads. Inferior bracts of involucre leafy, toothed, lanceolate, longer than the flowers. Stamens woolly, 2 stigmas.
Woods and pastures; 4300-6500 feet; local.
Carpathians, Servia, Eastern, Central, and Western Alps; Pyrenees, Spain.
Flowers in panicles, racemes, or spikes, or rarely solitary, and occasionally in short, leafy heads. Corolla regular, bell-shaped, broadly tubular or rotate, with 5 broad lanceolate lobes. Anthers distinct. Stigmas 2, 3, or 5. Capsule crowned by the lobes of the calyx and dehiscing laterally or at the top. A numerous genus, widely spread over the globe, chiefly in the northern hemisphere or in mountain ranges of the hotter regions.