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.
Annual. Stem erect, simple, hairy and leafy below, glabrous and naked above. Leaves oval, entire or toothed; stem-leaves sessile, close together, not auricled. Flowers yellowish, small. Petals emarginate. Fruiting-spike elongated, loose, with spreading pedicels 2 or 3 times the length of the silicules, which are oblong and pubescent. Style almost wanting.
Woods and screes in the mountains. May to July.
Savoy, Eastern Pyrenees, Caucasus. Europe from Spain to Scandinavia; Asia, N. America.
Annual. Stem erect, slender, hisped with bifid hairs, leafy. Radical leaves oval, toothed, petioled; stem-leaves distant, amplexicaul, strongly toothed. Flowers white, very small, in a loose spike, with spreading pedicels. Silicule elliptic.
Walls, rocky and shady places in the plains and hills. April to June. Local.
Rare in Switzerland (Bale, Martigny, etc.). Almost all Europe; Western Asia, Canada. British.
Plant greyish white, with stellate hairs. Stem erect, very leafy. Leaves entire or toothed; the root-leaves in a rosette, lanceolate; stem-leaves oval or lanceolate, sessile. Flowers white, in a long spike. Silicules linear-oblong, on short pedicels, glabrous or pubescent, arranged densely on the axis.
Stony places and mountain pastures, both in the Alps and sub-Alps. Local in Switzerland. May to July.
Alps, Pyrenees; Northern and Central Europe; Caucasus, Iceland. Asia, N. America.
This little annual plant, so well known in England, and so variable, is common in various forms and varieties in Switzerland, and ascends the Alps of Central Europe to the Pine-forest zone at least. February to May.
Europe, Asia, Africa, N. America. British.
Sepals short, spreading. Flowers small, white. Pods many-seeded.
A very small genus scarcely distinct from Cochlearia.
Stem erect, 6-12 inches high, glabrous like the leaves, or slightly hairy in lower parts, usually branched. Root-leaves in a rosette, oblong, obtuse, entire or toothed, slightly hispid; upper leaves lanceolate, obtuse. Flowers milk-white. Silicules glabrous, oboval. Style very short. Six seeds in two rows.
Rocks and stony places in the calcareous Alps and lower Alps (e.g. the Saleve and Mole) and descending sub-alpine valleys. May to August.
Alps, Jura, Cevennes, Corbieres, Pyrenees, Var, Central and Southern Europe from Spain to Greece.
Flowers small, yellow. Pod obovoid, valves very convex, midrib distinct, with flattened edges forming a narrow margin round the pod. Style slender. Erect annuals with auricled leaves.
A genus of only about 3 species (Europe and North Asia) growing in crops. Bentham said they may "possibly be reducible to one species".
In Switzerland botanists have named three forms: C. sativa Crantz, which is subspontaneous here and there, C. microcarpa Andrz., and C. Alyssum Thellung, which is usually found in fields of Flax.
One of these forms we noticed in 1911 in a field where Flax had been previously grown at 4500 feet, near Argentiere in Haute-Savoie.
 
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