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, or rarely perennial, erect herbs, glabrous or with spreading hairs. Flowers small, yellow or white. Pods linear, nearly cylindrical, the lateral nerves of the valves more or less distinct. Stigma entire, small or capitate, closely sessile on the summit of the valves. Seeds in a single row, ovoid or oblong, not flattened.
A large genus spread over the northern hemisphere, but with very few Alpine species.
Stem 2 feet high or more, erect, branching at the top, very leafy. Leaves pinnatifid, with numerous lanceolate, incised, dentate lobes, pale green. Flowers yellow, small. Sepals 2-3 times shorter than the pedicel. Fruiting-spikes short, in corymbose panicles, with erect pedicels. Silicules ascending, short, compressed. Valves with 1 nerve. Seeds large, oval, brown, finely spotted.
Pastures and stony places in siliceous mountains, especially in the Mountain Alder zone. July, August.
Savoie, Dauphine, Provence, Central Pyrenees, Spain, Piedmont, as at Mont Cenis. In Switzerland only in Valais.
A useful plant for the shadier parts of the rock garden among big stones; the foliage being handsome.
A large perennial species, 3 feet or more high, erect, branching, and very leafy, pubescent. Leaves lanceolate, entire, or toothed, often glandular. Flowers yellow, larger than in most species, fragrant. Sepals shorter than the pedicels, which are erect, but spreading. Silicules spreading or curved, long, cylindrical, slender. Valves with 3 nerves. Seeds linear-oblong, brown, glossy, in one row.
Hedges, roadsides, and thickets in the sub-alpine region, local. June to August.
Alps of Savoy and Dauphiny, occasionally in Switzerland (Engadine, etc.), Central and Eastern Europe.
Erect annuals or perennials, pale or hoary, with closely adpressed hairs, rarely quite glabrous. Leaves entire or slightly toothed. Flowers yellow or rarely white. Pod linear, nearly quadrangular from the prominent midrib of the valves. Stigma broadly capitate, or with short, spreading lobes. Seed ovoid or oblong, the seed-stalk not flattened.
A rather numerous genus in the northern hemisphere; differing from Wallflower and Sisymbrium in the seed-pods.
Root thick. Stem angular, 9-18 inches high. Leaves linear-lanceolate, entire or slightly toothed. Flowers large, lemon-yellow and then straw-coloured, scented. Sepals dilated at the base, 1-3 times longer than the pedicel. Pod compressedly 4-edged. Style 3 times width of pod. Stigma 2-lobed.
Rocky places in the Alps and sub-Alps. May, June.
Jura (Dole, Reculet, etc., not otherwise in Switzerland), Mont Ventoux, Corbieres, Pyrenees, Spanish Peninsular, Carpathians.