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.
Usually glabrous, 4-15 inches high, biennial or perennial, forming a branched or tufted stock, with obovate-oval or oblong, stalked, radical leaves. Stems simple, erect or ascending. Stem-leaves narrow, clasping the stem with small auricles, entire or toothed. Petals white, occasionally pinkish. Pod oboval, winged at the summit, less broad than in T. montanum or T. perfoliatum, slightly emarginate. Style prominent, as it is in T. montanum.
Mountain pastures and rocky places, especially on limestone in the Alps, sub-Alps, and plains. May, June.
'Western and Central Europe, extending northward to Southern Sweden. Himalaya. British.
In Switzerland, the Jura, and elsewhere at least two sub-species are known, viz.: T. brachypetalum Jordan, whose anthers remain yellow after pollination, and T. sylvestre Jordan, whose violet anthers turn blackish after pollination. T. virens Jordan is sometimes considered a distinct species. Its leaves are a bright green and the flowers are larger than in alpestre. The style is also longer and more prominent. The anthers are violet and then blackish. It is usually found at higher elevations, at any rate in Switzerland.
A glabrous and glaucous plant, 6-10 inches high, with stoloni-ferous shoots springing from the rootstock. Stem simple. Radical leaves oblong, petioled; stem-leaves oblong, auricled or heart-shaped, sessile. Flowers rather large, Petals twice the length of sepals. Anthers pale lilac. Pods oboval, rounded at base, with a broad shallow notch, and rounded, obtuse wings. Style prominent. Seeds shining, 1-2 in each cell.
Hills and rocky places, especially on limestone. April to June.
Central and Eastern France, Eastern Pyrenees, Jura, rare in Switzerland. Central and Southern Europe.
This beautiful violet or mauve-coloured species (described and figured in Alpine Plants of Europe, p. 62, is usually seen only on detritus at high elevations, but Mr. Reginald Malby has a photograph of it growing in a river bed in Switzerland at the remarkably low elevation of about 3000 feet.
Glabrous or minutely downy annuals or branching perennials, with narrow or pinnatifid leaves, and white or pink flowers, 2 adjoining exterior petals larger than the 2 others. Filaments without appendages. Pod orbicular or oval, laterally flattened, notched at the top, the valves boat-shaped, the keel or midrib expanded into a wing. One seed only in each cell.
About 20 species inhabiting Southern Europe, Asia Minor, and Algeria, of which several are cultivated under the name of Candytufts, and all readily known by the unequal petals.
Stem 5-10 inches, woody and twisted at the base, diffuse, trailing. Flowering-stems glabrous. Leaves smooth, linear, oblong, obtuse, entire, ciliated, numerous, and close together. Flowers white, rather large. Sepals whitish at the borders. Filaments violet at the top. Fruiting panicle rather loose, with spreading pedicels. Silicules large, oval, broadly winged, each lobe pointed. Style passing beyond the lobes.
Rocks and stony places in the mountains. June to August.
Pyrenees, Corbieres, Basses-Alpes; Southern Europe from Portugal to Greece; Asia Minor.
This is the commonest perennial Candytuft. Being half-shrubby, dwarf, and evergreen it is a useful edging for beds or shrubberies, for on any soil it quickly forms low masses of dark green foliage, which in April and May in England change into sheets of white. It loves the sun, and can be increased by seed or from cuttings.