THE CAMPIONS N . R.
IT was very encouraging to learn at our A.G.M. last March of the increasing membership of our Society. From personal contacts I realise that many of our new members are newcomers to Suffolk; several are retired folk who have, perhaps for the first time in their lives, the time and opportunity to take an interest in the countryside around them. Many have, I know, very little knovvledge of even the common species of field and hedgerow and though shy of displaying their limited knowledge, are, none the less deeply interested in, and avid for, further information about, the wild life, the natural history, of our area. We ought as a Society, to recognise that we shall increasingly attract members of this kind and I suggest that we have a duty, as a Natural History Society, to offer them the opportunity of satisfying their curiosity. It was with such people in mind that I have chosen as the subject of this article, some very commonplace plants, hoping that I may be able to show that even the very ordinary species around us may have features of absorbing interest to the amateur naturalist. I have chosen those two common, local species, the red and white campions, which will soon be in bloom in the hedgerows of this County. The taxonomists have, over the years, given them a variety of Latin names; they were in the genus Lychnisâ€”the red was Lychnis dioicum (Linnaeus) then Lychnis diurna the white, Lychnis alba, then Lychnis vespertina then both were placed in the genus Silene, but were later re-named Melandrium rubrum and Melandrium album, under which names they appear in our current floras. The habitats of these two give interesting clues as to their origins. The Red Campion is a typical woodland species, in association with the bluebell, occurring in, or more accurately, about, the fringes of our local woods. It is a fair assumption that it came to Britain, spreading with our many deciduous woodland species, after the Ice Age and is, in this sense, truly indigenous. It thrives on the light soils of Suffolk and, like the common nettle, particularly on those rieh in nitrogen, where man adds his wastes to the local soils. When, in earlier centuries, the great woodlands of East Anglia were felled, used and burned, the Red Campion, like other woodland species, found a refuge in the hedgerows, which were planted to divide one field from another, a habitat similar in many respects to the woodland fringe. T h e White Campion is a plant of arable areaâ€”a "weed" associated with cereal crops. This suggests that it may well have been introduced with the Neolithic groups who came to these
islands as late as 2,500 B.C. bringing their cereal seeds and, as impurities, seeds of the common v.ecds of arable cultivations, which spread with them along the chalky downlands of Southern England. It is significant that in neighbouring Cambridgeshire, an arable chalk-soil area, Red Campion is a rare species protected in the County, but the white is a common denizen of the hedgerows, to which it has escaped from the arable fields. In the hedgerows then, the two species meet. They have their differences; the red, as may be expected, seems to be more robust, growing as a biennial or perennial of a few years duration; the white, less hardy, may succumb in a hard winter and is often an annual or biennial in a protected site. Both species are dioecious, an unusual condition in flowering plants, each individual plant being either male or female. The sexes are easily distinguishable by the flowers, the male having five stamens in the throat of the corolla, and a narrow tubulĂ¤r calyx showing ten veins, the female flower has a Stigma of five finger-like processes protruding from the throat and a larger, ovoid calyx with twenty veins, accommodating the ovary which will swell, when fertilized, to burst open the calyx. The Campions were the first plants in which the sex-chromosomes were identified. Like the mammals, including ourselves, the female has the paired somatic chromosomes (eleven pairs) plus two X chromosomes, the male the twenty-two somatic and an X and a Y chromosome in the diploid cells. The reproductive cells in the ovules have all 1 1 + X , but half the pollen grains contain an X, the other half a Y chromosome. As in mammals, the sex of the offspring is determined by the male cell which effects fertilisation. The Red Campion is scentless but has nectaries at the base of the corolla tube and attracts bees and hover-flies, which carry pollen from male to female flowers. The White is eveningscented, attracting moths at dusk, as pollinators, passing from flower to flower to seek the nectar. Where, as in many local hedgerows, the two species occur together, hybrid swarms of pink campions, crosses between the species and intermediate in their colouring and other characteristics are commonly found. Was the cross-pollination effected by the day-flying bees and hover-flies or the night-flying moths? Observation by naturalists would be interesting. Hybridisation between the pure red or white species and the cross-bred pinks produces a whole rĂ¤nge of interesting intermediates. The relationship between moths and campions involves parasitism: two moths, the Lychnis and the Campion, have evolved the habit of laying an egg in the corolla tube of the flowers they visit. T h e larva, hatching from the egg, gnaws its way into the
Suffolk Natural History, Vol. 16, Part 4
ovary and feeds on the developing seeds, eventually consuming all, after which it bites its way through the ovary wall, leaving a hole in the capsule, and makes its way down into the soil to pupate. The holed capsule, empty of the usual large brown seeds, is very obvious. The attack of these moths is fairly common in the white campions, records of occurence in pink or red campions would be welcomed. Another parasite which is commonly associated with the white campion is a fungus Ustilago violacea. Its effect is strĂ¤nge but very obvious. Female plants of white campion, parasitised by this fungus, develop flowers which apparently change their sex. Instead of developing the normal ovary and five-branched Stigma, they produce five stamen-like growths, as does the male flower, but the "anthers" of the false stamens instead of white pollengrains, produce thousands of purple-brown fungus spores, which are quite easily visible to even the casual observer, in the white flowers. These spores are carried by visiting insects, from infected to other flowers, and the disease is thus transmitted by seeds. Records of infection of the red campion or of pink hybrids would be very welcome. I hope that this brief paper about such commonplace species may encourage some of our members to look more closely at the plants which I have mentioned and observe, with no more equipment than sharp eyes and a little knowledge, the fascinating interrelationships which lead to the absorbing interest we find in our natural environment. N. R. Ken, B.Sc., Wheelwrighfs Piece, Freston, Ipswich.