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 Meadow Crane's Bill is often 3 or 4 ft. high. The flowers may be found from June to September. The plant is perennial, increasing by division of the root.
This well-known wild flower exhibits admirably numerous adaptations to cross-pollination. Dark lines on the petals converging towards the centre act as honey-guides, and indicate where the honey-glands lie at the base of the outer stamens. The hairs on the claws of the petals protect the honey from the rain. The flowers are large and conspicuous and wide open, and short-lipped insects can gain access to the honey.
The anthers ripen in advance of the stigma, which is a means of preventing self-pollination. When the anthers open, and in this stage hang over the stigma, the latter is incapable of being pollinated, all the stamens ripening, opening, and shrivelling before the stigma is receptive. Hence pollen must be borne by insects from other flowers before the plant can be pollinated at all, and as good seed is usually set this must usually be the case.
As the anthers wither the whorls of stamens bend outwards. When the anthers open the stigmas cannot be pollinated, but only when the anthers are farthest away from them. The visitors are Hymenoptera (Apidae, Apis mellifica, Osmia rufa, Chelostoma stelis, Andrena, Halictus, Prosopis); Diptera (Syrphidae, Melithreptus).
The Meadow Crane's Bill disperses its seeds by its own mechanism. The fruit is many-seeded, splitting into single parts that break off separately. When the seeds are ripe the carpels split, and the seeds are scattered by an explosive movement.
In the case of this species the carpels, which are hairy, not netted, are not thrown. It is the seed which is netted that is thrown by the same means as in G. Robertianum, by the tenseness of the rodlike attachment of the capsule.
Photo. B. Hanley - Meadow Crane's Bill (Geranium pratense, L.)
This plant is fond of peat and requires a humus soil, such as that afforded by loamy soil mixed with humus or a little peat - peaty loam.
The fungus Sphaerotheca humuli infests Geranium generally, and Uromyces Geranii grows upon this one.
A beetle, Coeliodes geranii, lives on it.
Geranium, Dioscorides, is from the Greek geras, crane, in allusion to the beaked fruits, and pratense alludes to its habitat, in meadows. The plant is called Crowfoot, Crane's-bill, Grace of God, Gratia Dei, the first from the resemblance between its foliage and that of some Buttercups.
The Meadow Crane's Bill has been cultivated in the garden, and is a beautiful, showy, and striking plant.
Essential Specific Characters: 67. Geranium pratense, L. - Stem erect, leaves palmate, 7-lobed, serrate, flowers large, blue, with ciliate claw, smooth stamens, tapered from broad base, capsule hairy, hairs glandular, spreading, seeds netted, fruit-stalks deflexed.