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 salt marshes, pastures near the sea, and waste places. The habit is more or less the grass habit. The stem is solid, wavy, ribbed, wiry, very slender, branched, erect or prostrate. The leaves are linear-lance-shaped, with a long1, narrow point, 3-nerved, rigid, the lowest slightly swollen upwards. The bracts are awl-like, unequal, 3-5, the bracteoles the same. The flowers are yellow and very small, in umbels or stalkless, in the axils or terminal, the partial umbels of 3-5, overtopping the involucre, in a raceme, or more or less spikelike along the branches. The fruit is broad, small, granulate between the 5 prominent ridges. There are no vittae. The plant is 6-12 in. in height, and flowers between July and September, being a herbaceous annual.
The habitat of this plant is wet places, marshes and ditches, especially near the sea. The plant is erect in habit, and has a strong scent. The root is spindle-shaped. The stem is smooth, erect, stout, grooved, branched, and leafy. The leaves are pinnate, with lobes each side of a common stalk, or trifoliate. The leaflets in the upper leaves are wedge-shaped, those of the radical leaves are stalked, round -lobed. The flowers are small, greenish-white, in stalkless or shortly-stalked terminal or lateral umbels, with no partial involucres, with one or two leaves, with leaflets in threes. The petals are hooded. The fruit is round. The styles are short, bent back, and spreading. The plant is 1-3 ft. high, flowering between June and August, and is a herbaceous biennial or perennial.
The habitat of this plant is sea cliffs, rocks, and walls. The habit is erect. The stems are branching, round below, finely furrowed, polished, filled with pith or nearly solid. The leaves are dark-green, much divided, 3-4-pinnate, shortly-stalked, with many slender, linear lobes, hair-like, limp, channelled, the upper long. The flowers are small, yellow, in large bluish-green, concave umbels, with many rays. The fruit is egg-shaped. The plant is 3-5 ft. high, flowering in July and August, and is a herbaceous perennial.
The habitat of this plant is rocky coasts, sea cliffs in northern Britain, rocks on the northern sea-coast. The habit is the rosette habit. The rootstock is stout, branched. The stems are erect, little branched, nearly simple, hollow, round, grooved, herbaceous, tinged with red. The leaves are dull-green, mainly radical, twice ternate. The leaflets are egg-shaped, rhomboidal, or round to heart-shaped, toothed, opaque, large, lobed or cut, scalloped. The flowers are white or pink, nearly regular, in umbels with 8-12 rays. The involucres consist of 5 7 leaves, the bracts are few, and the bracteoles linear to awl-like. The calyx is 5-toothed. The fruit is brown, the ridges winged, the interstices with 3, the commissure with 6 stripes. The seed is free. The style is short, bent backwards. The plant is 9 in. to 3 ft. high, flowering in July and August, and is a herbaceous perennial.
The habitat of this plant is maritime marshes and cliffs, salt marshes. The habit is erect. The stems are rounded, solid, furrowed. The leaves are five times ternate, oblong. The leaflets are linear, limp, long and narrow, acute. The flowers are small, yellow, in a large umbel, on spreading, more or less opposite, branches, with many rays, spreading. The central flowers are imperfect. The involucre consists of 3 bracts which soon fall, and the bracteoles are short and thread-like. The ultimate flower-stalks are slender, longer than the fruit. The fruit has narrow wings, and the stripes of the commissures are superficial. The styles are stout, bent back. The plant is 2-3 ft. high, flowering from July to September, and is a herbaceous perennial.