Yellow-rattle, like the pernicious field weed Red Bartsia, obtains its nourishment by semi-parasitic means. The young germinating plant is particularly energetic in its efforts to find a host, sometimes even attaching itself to the roots of another sprouting plant of its own kind.
Once it finds a host – more usually a cereal grass – it absorbs mineral substances from this source. Organic substances it obtains for itself by photosynthesis in the leaves, just like other green plants. The calyx of the Yellow-rattle increases in size as the plant grows. By the time the seeds are ripe it is almost spherical and strikingly inflated. The ripe seeds drop out from open fruits into the swollen calyx as it dries and when the wind blows a mass of these plants makes an audible rattling sound, which is what gives the plant its name.
Field Fennel also features in the language of flowers: the sending of a bunch of these flowers to a lover symbolizes rejection of love. Or, where this plant is known as St Catherine’s Flower, it is because the structure of the flower and bracts resembles the wheel on which prisoners, such as St Catherine, were tortured.
Black Nightshade is found practically throughout the world, in fields (particularly in root crops), field compost heaps, and waste places , although it once grew only in southern Europe. It tolerates long periods of drought, is generally restricted to warmer regions, but is occasionally seen in mountains, and will survive the first mild frosts of autumn.
Black Nightshade is an annual herb multiplying by means of seeds – as many as 40,000 to a plant. The seeds germinate the year after ripening but not until the onset of summer weather, when the ground is warmed through. The plant grows to a height of 20-50 cm. The stem is angular, erect, and broadly branched.
However, this species of Rhinanthus does not occur in Britain. This is a plant 10-50 cm high which prefers a moist situation, particularly in spring. As it requires a great deal of light it is suppressed by a tall stand of grain.
