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 very characteristic seeds of this plant are unknown in a fossil state. The Northern Temperate Zone in Europe, North Africa, Siberia, Western Asia, as far east as N.W. India, is the limit of this plant's distribution. In Great Britain it is absent from Roxburgh, Mid Perth, W. Perth; and in Wales it ascends to 1200 ft. It is found in Ireland and the Channel Islands.
Stork's Bill is one of the familiar plants of the seaside, where it grows in association with other dry-soil or xerophilous plants, such as Hop Trefoil, Hound's Tongue, Plantago Coronopus, Hawk's Beard, and others. Inland it is found on the sandy soil of commons, waste places, golf-links, and places where the grass is turf-like, often on heaths; and it comes up also amidst the typical alien flora of the farm or garden.
This plant has a habit like Sandwort Spurrey, which also grows with it, being prostrate, with stems bent downwards, several from the root, thick, hairy, branched, with leaves with lobes each side of a common stalk, the segments being divided nearly to the base, stalkless, and narrow. The stipules or leaflike organs are lance-shaped and membranous, the upper entire, the lower divided into 2 nearly to the base.
The flowers are in umbels of 3-6 and rose-colour, with fugacious or falling petals, hairy at the base, and longer than the calyx. The flower-stalks exceed the leaves in length, and are many-flowered. The petals are unequal. The capsule is ribbed and beaked, the seeds are oblong, brown, the long awn becoming spiral finally, but influenced by hygroscopic deviations.
Photo. Rev. C. A. Hall - Stork's Bill (Erodium Cicutartum, L'herit.)
The plant is 9 in. to 1 ft. high. It flowers in April and the five succeeding months. It is a perennial.
The five inner stamens are rudimentary and produce no pollen. The flowers are proterandrous, the stamens ripening before the stigma. In the absence of insects the plant possesses the power of self-pollination, as the anthers lie close to the stigma, and is self-fertile. Honey is secreted as in Geranium. Only the five outer stamens produce pollen. Though the plant is prostrate it is rendered conspicuous in the sun, turning its petals to the sun, opening at 7 a.m., the petals falling by noon. The upper 2 or 3 petals bear path-finders or fine black lines, and the lower are lengthened and serve as an alighting place. The flowers are visited by Hymenoptera (Apidae, Apis mellifica) and Coleoptera; the last fall off unless they cling on tightly.
The Stork's Bill is dispersed by its own agency. The seeds are expelled from the pod by an elastic movement, and are drawn into the ground by a similar hygroscopic arrangement. The carpels do not open but are contracted with the seeds still enclosed, the awn remaining attached. The layers of the cell-wall consist of lamellae of different densities and refractive indices. In the one the cells are elongate and woody in concentric series, being light and dark alternately. These last are the edges of the lamellae. The parallel lamellae in two series are inclined to the axis at different angles, or wind spirally in opposite directions around the lamellae. The expansion of the cell-wall tissue during imbibition is caused by the swelling of the striae of less density, and the imbibition of the water in all probability sets up spiral tension, producing a twisting motion. Further single cells roll up as shown by Francis Darwin. Or the twisting of the awn may be due to the difference between the contraction of the woody fibres and the comparatively soft parenchyma or thin-walled cellular tissue, in which the cells are not much longer than broad. The more complete lignifica-tion of the outer cells, which contract more than the inner, may be the reason, the spiral twisting being due to the curving of the woody bars with the hollow side upwards. Moistness regulates the amount of the twisting of the awn, which twists and untwists with variation in atmospheric humidity, being thus hygroscopic. The fixing of the awn during the process of untwisting causes the seed to be driven into the ground. The seed vessel is so sensitive the arista or awn curls up under the influence of the heat or moisture of the hand. The elastic movement of the seed to promote dispersal is one of the most interesting examples of sensitiveness.
Stork's Bill is almost entirely a sand plant, growing almost always on sand soil. By the sea-coast it is a halophyte, living on a saline soil.
The Brown Argus (Lycaena astrarche) feeds upon it, also Geotomus punctulatus and Heterogaster urticae, Hemiptera Heteroptera.
Erodium is from the Greek Erodios, a heron, in allusion to the shape of the fruit. Cicutarium is from cicuta, hemlock, because the foliage resembles that of hemlock. The plant is called Wild Musk, Pink or Powk Needle, Stickpile.
Essential Specific Characters:69. Erodium cicutarium, L'Herit. - Stem prostrate, spreading, downy, leaves pinnate, leaflets sessile, pinnatifid, stems many-flowered, flowers lilac, in umbels, stipules lanceolate, stamens dilated.