This section is from the book "British Wild Flowers - In Their Natural Haunts Vol2-4", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
The antiquity of this umbellifer, in spite of its association with cultivated land to-day, is shown by its occurrence in Neolithic beds in Hants, and Roman deposits at Edinburgh.
It is found in the Temperate Zone in Europe and Siberia, and it has been recently introduced into N. America. In Great Britain it is not found in Cardigan, Isle of Man, Linlithgow, Easterness, and only in the Clyde Islands, in W. and N. Highlands, and in the Northern Isles, or from Elgin to the S. Coast. It is native in Ireland.
Fool's Parsley is a very characteristic plant of all cultivated ground, occurring there and elsewhere always as a weed. It is also a common plant around houses, in gardens, plantations, stack- and farm-yards, and is found on all pieces of waste land.
The burning properties of the plant, when taken, are referred to in the first Latin name. It is poisonous, and this may be indicated by its extremely smooth, shiny stem, and dark-green lurid colour. The main stem divides above, and the leaflets are all linear, narrowly elliptic, of one size, the leaves being several times divided, with lobes each side of the stalk. The stem is hollow and bluish-green. The leaf-stalks have small membranous sheaths, and are ascending and furrowed.
The flowers are in umbels, and white, with smaller rays in the centre. There are no general bracts or leaves, and no general whorls of leaf-like organs. The partial involucres have bracts all one side, long and pendulous. The flowers are irregular, with no calyx-teeth, and notched petals. The fruit is green and finely furrowed. The Fool's Parsley is usually 1 ft. to 18 in. high. It is in flower from July to September. It is annual, and increased by seeds.
The flowers are white, small, and inconspicuous. As the plant has a disagreeable odour and is poisonous, it is on this account little, if at all, visited by insects. The petals are turned in, and the stigmas as well as the 5 turned-in stamens are short, and below the corolla, or more properly the stamens overtop the ovary, which is glandular. Self-pollination is therefore encouraged. Opinion differs as to whether the perfect flower matures the stigma or anthers first.
The seeds being flattened are more readily wind-carried, and when the old stems are dry the seeds are easily jerked out to a distance by wind or passing animals.
Fool's Parsley grows on sand soil, and is a sand plant, but it will grow in the shade on clay as well, though it is most prevalent on rock soils yielding a sandy loam, and limestone soils, those yielded by such geological formations as the Lias and the Great Chalky Boulder clay, to mention two out of many suitable formations.
Photo. B Hanley - Fool's Parsley (Aethusa Cynapium, L.)