Many of these seeds are well worth studying, whether we are interested in seed testing or not. The corn buttercup and the wild carrot have curious spined seeds; those of the larkspur when magnified appear to be studded with little shreds of paper. White and red campion, have kidney shaped seeds studded with warts and so similar to one another that the microscopist who can distinguish one from the other may consider himself something of an expert. Spurrey has lens shaped seeds with raised equator-like rims. Evening primrose seeds are curious because they are found in all sorts of shapes. The seeds of rib-wort plantain resemble miniature date seeds, others resemble minute bananas, some are perfectly round, others almost square; some have smooth shining surfaces which look as though they had been artificially polished, others again are wrinkled and deeply furrowed; but, most curious of all the common seeds are those of the cornflower, they resemble nothing so much as little shaving-brushes, with bright yellow bristles. Many profitable hours may be spent in studying the seeds of our common native plants, both wild and cultivated. There are two specially obnoxious plants whose seeds may be mixed with agricultural seed, to the dismay of the farmer. We refer to Broomrape and Dodder, both of them unable to earn their own living and depending for their existence on the robbing of other plants. Broomrape usually attaches itself to the roots of Hazel, Poplar or Beech and steals its food therefrom, but its fleshy pink stems and flowers may sometimes be seen in clover fields, then clover is its victim. More common and more destructive is the little Dodder, a member of the Convolvulus family. Its seeds are very minute and when they germinate they give rise to a seedling not unlike a piece of wire. With one end fixed in the ground, the other waves about till it finds a clover plant round which it twines and not only so but it sends out suckers which microscopic examination shows, penetrate the stem of the clover to rob its food. By pulling a Dodder stem away from the clover we can clearly see a number of holes where the suckers have entered. Fungus diseases and insects wage constant warfare on the farmer’s belongings. That we may better understand the structure of the disease-causing fungi we are about to examine, let us refresh our memories concerning that very common fungus, known as white mould and mentioned in an earlier chapter. The reason fungi cause damage to other plants, the one invariable reason, is that they, being unable to manufacture food for themselves, steal it from the plants on which they grow. Some of them are parasites and steal their food from living animals or plants; others live upon dead animal or vegetable matter and the white mould is one of the latter fungi.