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.
A family represented in Europe by a single genus.
Leaves radical or alternate, stipulate. Flowers axillary, solitary, or in cymes, with 2 small bracts. Sepals 5, usually unequal, and produced at the base beyond their insertion. Corolla irregular, of 5 spreading petals, the lowest produced into a spur at the base. Style single, with a dilated or thickened or hooked stigma. Capsule 1-celled, 3-valved. Seeds attached to 3 parietal placentae.
There are about 150 species of Viola spread more or less throughout the globe.
Glabrous. Leaves all radical, digitate, multi-partite, with obtuse teeth. Flowers pale violet or blue, rarely white, fragrant. Petals small. Capsule trigonous.
Stony, rocky places in the Alps from 4500-7000 feet. June, July.
Eastern, Central, and Western Alps; very local. Rare in Switzerland and commoner in Tyrol and Carinthia; Ural Mountains, Siberia.
Rootstock cylindrical, scaly, fleshy, oblique, branched above. Stem erect or ascending, limp, glabrous like the flowers and leafstalks. Leaves reniform, crenate, obtuse, or shortly acuminate, finely ciliated, otherwise mostly glabrous, bright green. Stipules ovate-lanceolate, acute, entire. Flowers usually 2 in a leaf-axil. Petals yellow, the odd one streaked with brown at the base. Calyx-teeth acute. Stigma abrupt, hollow, somewhat 2-lobed. Capsule elongated, obtuse, glabrous, pendent.
Bushy, stony places and damp rocks, and in moist mountain woods; 4000-9000 feet, though rarely above 8000 feet. June to August.
Throughout the Alpine Chain; Carpathians, Scandinavia, Jura, Corsica, Pyrenees: Asia, from the Urals and Caucasus to India; N. America.
Easily grown in a deep loam with plenty of leaf-mould, and thrives in half-shade, especially among damp boulders and under dripping rocks or in shallow caves.
1. VIOLA CALCARATA I.
2. V. PIFLORA L.
3. V. MONTANA I,.
4. V. ALPESTRIS (DC.) WITTR.
5 V. SYLVATICA FRIES.
4 7 NATURAL SIZE.
Leaves crenate, ovate, the upper ones lanceolate. Stipules entire, tripartite, or pinnatifid. Stem 1-flowered, erect, 3 inches or more in height. Flowers at least an inch in diameter, usually violet-blue, rarely yellow or white. Spur as long as corolla, i.e. at least 3/4 inch, and so long and narrow that only butterflies with a sufficiently long proboscis can penetrate as far as the nectar at its extremity. Plant glabrous, branched, and leafy at the base, with creeping runners.
Alpine pastures from 5000-9000 feet, often so abundant as to form a carpet of violet-blue. June, July.
Eastern, Central, and Western Alps, Jura, Apennines, Central and Southern Europe from Bavaria to Sicily and Greece.