How Plants Defend Themselves
In May the hedgerows will be full of flowers. I have not room to describe them all to you. You should pick one of each, on your way to school, and ask your teacher about them. On the tops of the banks, and nestling in the wood, you will find the wild hyacinths, which children call bluebells, and the red ragged-robin, and the lovely starworts or stitchworts with flowers like pure white stars and narrow pointed leaves. Children call these "snap-jacks," because the seed-box, when it is ripe, snaps if you pinch it. There are many kinds of starworts. One of them with small flowers is called chickweed.
The meadows are now golden with buttercups, and the ditches are blue with forget-me-nots, and you can find the little blue Speedwell or Bird's-eye almost anywhere. It is a weed, with thin weak stalks, and you may know it by its four blue petals, and its two stamens standing out like horns. Before long the tall Meadow-sweet, with its clusters of tiny white flowers, will be blooming by the side of the streams and in damp places; and the pretty little Bird's-foot Trefoil will brighten the hedgerows and fields.
You will know this little flower well. It grows quite low down, and is like a very small yellow pea-flower. About four or five little blossoms grow on the top of each flower-stalk, and the buds have bright red streaks upon them. When the pods are ripe they stand out like the toes of a bird's foot.
These, and many other flowers, you can find in the fields and hedges and you know now how to look for their seed-boxes and dust-bags; and I am sure you will watch to see what flies and bees and beetles come to fetch honey and pollen-dust.
If you do this and keep your eyes open, you will find out that other creatures come to the plants and flowers, which are not as useful to them as the bees. There is the cow, which takes large mouthfuls of their leaves as she grazes. There is the donkey, which feeds on the thistles. There is the rabbit, which comes out in the evening, to nibble at the tender young shoots; and there are the little field-mice, which scrape away the earth and feed on the thick stems and roots underground.
Now let me tell you of a few plants which protect themselves, and perhaps you can find more. First come the Anemone and the meadow Buttercup. Both these have bitter leaves which burn your tongue when you bite them. If you walk across a field which has many buttercups in it you will find that the cows and the sheep have left them alone as much as they can. If they eat the leaves, they will not touch the flowers, which are much the most acrid. So these plants prevent the cows from killing them. In the same way the leaves of wild geraniums have a disagreeable taste and smell.
Then there are the Ferns. They have a great deal of bitter tannin in them. You will find that if cows or sheep have been feeding where the Bracken fern is growing, they will not have touched it. So the ferns keep themselves safe.
Then the little Wood-sorrel tastes acid, and the Speedwells dry up the inside of your mouth if you eat their leaves. So these plants are left alone. Lastly the Parson-in-the-pulpit has such poisonous berries, leaves, and underground stems, that no animal will eat it above ground, and no sensible field-mouse would think of nibbling at it underground.
Then there are the plants which grow thorns on their stems. Cows and horses do not like to eat gorse for it hurts their tender mouths. These are a few examples. I cannot give you more, because I want to tell you of something even more curious.
Plants want bees and flies to visit their flowers, because they carry their pollen from flower to flower. But other insects, such as ants and spiders, like honey too, and they only crawl; they rub off any dust which falls on them before they reach another flower. So they rob the flowers of their honey and do nothing in return.
How do you think the plants protect themselves? In many different ways. The Teasel has a large flower-head full of honey. But the ants cannot steal it because its leaves grow opposite to each other on the stem, and join round it so that they make a little basin. The dew and the rain collect in the basin, and stop the ants from creeping past.
Then the plants we call Campions, of which the ragged-robin is one (p. 43), often have their flower stems covered with fine hairs, and the stem near the flower is very sticky. When the ants climb up to try to steal the honey they stick fast, and can get no further. This is why some of the campions are often called "catch-flies."
A very common plant in the hedges is the Sun-spurge (p. 43), which has curious small green flowers. This plant has a poisonous milky juice in its stem. When the ants try to climb up, they prick holes with their claws, and stick fast and die.
I wish I could tell you more of the way in which plants protect themselves by prickles, by hairs, and by poisons, but you must look for yourselves.
Bring in sun-spurge, campion or catch-fly, wood-sorrel, bracken, teasel, and wild geranium.