This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
The habitat of this plant is moist waste places, watery places. The habit is creeping, then erect. The rootstock is creeping. The stem is wavy and angular. The leaves are divided to the base, each side of a common stalk, with numerous oblong, lance-shaped leaflets, the uppermost leaves sometimes nearly entire. The flowers are in short racemes. They are yellow, with petals twice as long as the calyx. There are six disk-glands. The pods are linear, on spreading stalks, and are spreading or ascending, as long as the stalks or shorter. The seeds are very small, hardly in 2 rows. The plant is 9-18 in. in height, and flowers between June and August. It is a herbaceous perennial.
The habitat of this plant is damp places. The habit is erect or ascending. The stems are erect or ascending. The roots are fibrous. The leaves are deeply divided nearly to the base, or with lobes each side of a common stalk, the lobes few, broad, oblong, toothed, unequally cut, the terminal leaflet of the lower leaves the largest. The flowers are small, yellow, the petals not longer than the sepals. There are 4 disk-glands. The pods are short, turgid, linear-oblong, thick, ascending, as long as the stalks, which are spreading or bent down. The seeds are angular. There is a short style. The plant is 6-18 inches. It flowers between June and October, and the plant is a herbaceous perennial.
Barbarea stricta Fr. (= B. parviflora, Fr.). - The habitat of this plant is river-banks, etc. The plant has the rosette habit, with an erect stem. The radical leaves are lyrate, the terminal lobe larger, the upper pair of lobes small, shorter than the breadth of the terminal lobe, which is large and oblong to egg-shaped. The lateral lobes of the lower leaves are small. The upper leaves are entire, toothed. The flowers are smaller than in B. vulgaris (hence parviflord), in a close, narrow raceme, the flower-stalks erect. The petals are half as long again as the sepals. The flowering buds are downy. The pods are short, closely pressed, with an awl-like point. The plant is 1-2 ft. high, flowering from May to July, and is a herbaceous biennial.
The habitat of this plant is moist places and open ground. The plant has more or less the rosette habit. The stem is not wavy, stiff, erect and leafy. The radical leaves form a rosette. The leaves are pinnate, with the leaflets of the lower leaves round, angular, or toothed, those of the upper leaves narrower, oblong, entire, oval, cut. There are no stipules. The flowers are white, with erect petals, which are twice as long as the calyx. There are 4 stamens. The style is short, stout, equal to or half the breadth of the pod. The pods are erect, as are the stalks. The plant is from 6 in. to 2 ft. in height. The flowers are in bloom between April and September. The plant is a herbaceous -perennial.
The habitat of this plant is river-sides, moist meadows near streams, watery places. The habit is as in the last. The rootstock is slender, however, and bears stolons. The stem is ascending, angular, smooth or hairy. The leaves are alternate, pinnate. The leaflets in the radical leaves are more or less round or ovate, those of the stem narrow, oblong, deeply toothed. The stem-leaves have angular leaflets. The flowers are creamy-white, and large. The petals are three times the length of the calyx, and erect, large, inversely ovate, spreading. The stamens are as long as the petals. The anthers are purple or violet. The style is long and slender. The stigma is small. The pods are erect, and borne on slender stalks. The plant is 1-2 ft. in height, and flowers from April to June. It is a herbaceous perennial.
The habitat of this plant is ditches, corners of fields, river-banks, waste places. The plant is tufted in habit. There is a stout, long, cylindrical root-stock. The leaves are linear to oblong, blunt, scalloped. The radical leaves are long, stalked, wavy, with reticulate veins, heart-shaped, wedge-shaped, or unequal below. The stem-leaves are stalkless, lance - shaped, serrate, toothed. The young leaves are pinnate. The flowers are borne in racemose panicles, and are white, the petals twice as long as the calyx. The style is slender, the stigma is large and shield-shaped, pin-headed. The pods do not ripen in the British Isles, the immature ones being inversely ovoid, borne on long, slender stalks. The pouch is ovoid, 4-seeded. The plant is 2-3 ft. in height. It is in flower in May and June, and is a herbaceous perennial. Awlwort (Subularia aquatica, L.). - The habitat of this species is gravelly bottoms of subalpine lakes in N. Wales. The habit is the loose rosette habit. The plant is small and submerged. The root consists of numerous densely tufted, long, white fibres. The leaves are radical in tufts, round in section, linear, tapering to an awl-like point, and are cellular. The flowers are few, small, white, submerged, borne on a naked scape. The pods are oblong, with few seeds, and small, borne on short, ascending stalks. The pale-brown seeds are minutely dotted. The plant is 1-3 in. in height, and flowers from June to August. It is a herbaceous perennial.