Springtime and Other Essays. Sir Francis Darwin
of one millimetre in three minutes.
The explosive male flowers of the nettle have a somewhat similar meaning. The young stamen is bent so that the upper end of the anther touches the base of the filament. On the inner concave side of the stamen are large cells, whose turgescence tends to unfold the filament: I do not know by what means the unfolding is prevented, but whatever the cause may be, it is at last overcome and the stamen uncurls with a jerk, and scatters forth the pollen. Here, as in the rye, the pollen is protected until the actual moment when it starts on its voyage through the air.
Another of the Nettle tribe, Pilea serpyllifolia—a plant often cultivated in our greenhouses—is also explosive, and its little puffs of smoke-like pollen have gained for it the popular name of the artillery plant. Its power of explosion must be of value to it as counterbalancing the disadvantage, to a wind-fertilised plant, of such a lowly habit.
The adaptations found in the female organs are chiefly such as increase the surface capable of receiving the pollen, and therefore increase the chance of fertilisation. A big stigmatic surface is common: not only is the receptive part of the style large, but it usually bears very large stigmatic papillæ, which gives a velvety hoary look to this type of stigma. In the grasses the three divisions of the stigma are always more or less conspicuous; and reach a climax, in this respect, in the huge beard-like tangle of the maize.
Some of the most interesting cases of wind fertilisation are those in which an isolated instance occurs in a Natural Order otherwise served by insects. Thus in the Rosaceæ, Poterium sanguisorba is wind fertilised, and has long pendent stamens, and a tufted stigma; while the closely allied Sanguisorba officinalis, although it secretes nectar (and this can only mean that it hopes to attract insects), retains the tufted stigma of its anemophilous relatives.
In the case of the Kerguelen cabbage (Pringlea antiscorbutica), the cause of its degeneration seems to be the want of winged insects on the wind-blown shores on which it grows. It has acquired some anemophilous characters—e.g., increased stigmatic surface and exserted anthers. Its flowers are inconspicuous like those of wind-fertilised plants in general, and it seems in fair way to lose its petals altogether—many flowers only retaining a single one. The entomophilous ancestry of Pringlea is clearly shown by the occasional remnants of coloured markings in the petals, like those which in other flowers serve as finger-posts to visiting-insects, and are called nectar-guides.
But these are digressions—sidepaths of tempting detail which have lured me from the straight highway. However, they have brought me back to the main road.
In Blomefield’s Observations in Natural History (p. 332), he points out that “however much the seasons may differ in different years, the phenomena generally follow one another in the same order. And it follows that those which occur together any one year, will occur at or nearly [at] the same time every other.” This indeed is what we might expect, from the circumstances of any interruption in the time of their occurrence, due to seasonal influence, necessarily affecting them all equally. One of the examples by which he supports his view is the parallel behaviour of the ground-ivy (Nepeta Glechoma) and the box-tree, whose flowers appear simultaneously on 3rd April, as an average date; while in a certain backward year they flowered later, but still close together—namely, 20th April and 19th April. There is to me an especial charm in these duets. Thus I like to imagine that the larch is waiting to put on its new green clothes till it hears the black-cap. Or is it that the larch rules the orchestra, and with his green baton signals to the songster to strike into the symphony? [11]
Shakespeare is right to make the daffodil come before the swallow dares, since according to Blomefield the average of seventeen annual observations gives 12th March for the daffodil’s flowering-day, and the swallow does not appear till 9th April at the earliest. Browning, too, is scientifically safe in letting his chaffinch sing now “that the lowest boughs and the brushwood sheaf round the elm-tree bole are in tiny leaf.” Indeed, the most dilatory chaffinch must have been singing since 19th February, and in fortunate seasons might have been heard on 7th January. A floral calendar may be useful as an interpreter in antiquarian problems. Thus Blomefield [12a] says that “the flos-cuculi, or cuckoo-flower of the older botanists, was so called from its opening its flowers about the time of the cuckoo’s commencing his call.” The botanist referred to may have been Gerarde, and the flower seems to be Cardamine pratensis, known as lady’s smock, also as the cuckoo-flower. Now the cuckoo begins his song (as the average of Blomefield’s seventeen years’ observation near Cambridge) on 29th April, [12b] and lady’s smock blossoms 19th April. [12c] The coincidence is but moderate, but it is cheering to find in Gilbert White’s Calendar, with its earlier South Country dates, that the events occur together: lady’s smock, 6th to 20th April; cuckoo, 7th to 26th April.
Wood-sorrel (Oxalis acetosella) was known as cuckoo-sorrel by the Saxons. In Stillingfleet’s Calendar of Flora (1755), it is said to flower on 16th April, and the cuckoo to begin his song on 17th April. It is pleasant to find, in a Swedish calendar of flora, that the cuckoo sings on 12th May, and the wood-sorrel flowers on 13th May. Lychnis flos-cuculi, the ragged robin, flowers on 19th May, and seems to have no kind of right to the name of a cuckoo-flower, though Gerarde remarks that it “flowers in April and May, when the cuckoo doth begin to sing her pleasant notes without stammering.” [12d]
I remember being told by a physician that a celebrated Polish violinist in his old age could not bear the sound of concerted music, but he would weep over a musical score of which he said, “These beggars don’t play out of tune.” This is also true of the great symphony of colour which the springtime unfolds. The trees are double-basses, and doubtless some are contra-fagotti, though I confess that I cannot speak positively on this point. Then come a mass of beautiful shrub-like plants which make up the rest of the string-band. As one who loves wind-instruments, I like to think that the flutes, oboes, and clarinets are the flowers of my vernal orchestra, decorating the great mass of stringed instruments with streaks and flames of colour.
In real music, we cannot say why certain sounds make an appropriate opening for a symphony; nor can we understand why the chorus of flowers should (as above pointed out) be led by mezereon (Daphne mezereum), followed by furze, hazel, the daisy, and the snowdrop.
Of course, their dates are not rigorously fixed: the plants just referred to vary in their dates of flowering in the following way:
Mezereon, 11th January to 2nd February;
Furze, 1st January to 4th April;
Hazel, 1st January to 20th February;
Snowdrop, 18th January to 16th February;
the mean dates being: mezereon, 22nd January; furze, 24th January; hazel, 26th January; snowdrop, 30th January. One cause of variation in the date of flowering is temperature, and in the early months of the year this is probably the principal cause. Temperature must in the same way affect the flowering of summer plants, though the result is not so striking as in the springtime. In my article “A Procession of Flowers” (in this volume) I have given the range of the dates of flowering for different months.
The spring is the happiest season for those who love plants, who delight to watch and record the advent of old friends as the great procession of green leaves and beautiful flowers unwinds itself with a glory which no familiarity can tarnish.
I cannot resist giving the names of some of the flowers that make this familiar show that February and March give us. Field-speedwell (Veronica agrestis), butcher’s broom, Pyrus japonica, primrose, red dead-nettle, crocus, dandelion, periwinkle, celandine, marsh-marigold, sweet violet, ivy-leaved veronica, daffodil, white dead-nettle, colt’s-foot (Tussilago farfara), dog’s mercury, buttercup (Ranunculus repens), hyacinth, almond-tree, gooseberry, wood-sorrel, ground-ivy, wall-flower. The order in which they occur is taken from the mean dates of flowering given by Blomefield. To a lover of plants, this commonplace list will, I hope, be what a score is to a musician, and will recall to him some of the charm of the orchestra of living beauty that springtime awakens.
SOME NAMES OF CHARACTERS IN FICTION [15]
To some readers