England, my England! Roses, the wars of the roses, the English rose. Roses are part of the history and culture of England and the English-speaking colonies, and their symbolic importance goes a long way back in time.
Wild roses, like this sweet briar (Rosa rubiginosa) in Canterbury, don't look much like the cultivated roses in most people's gardens. Why not?
A flower is a specialized branch, with four kinds of leaves: sepals, petals, stamens, and carpels. How they develop is governed by a set of floral homeotic genes. If one of these genes is non-functional due to a mutation, some of the kinds of floral leaves don't develop properly, or they develop into the wrong kind of leaf. Many cultivated roses have their stamens converted into petals, so instead of five petals like the flower above, they have lots, and they don't produce pollen. Plants with flowers like those, called double flowers, tend not to reproduce, so the mutant form of the floral homeotic gene tends not to survive in wild populations, but it is successful in cultivation because the extra petals add to the showiness of the flowers. Gardeners select these sterile mutants and propagate them. Carnations are a similar cultivated double form derived from wild pinks.
The rose family has a huge diversity of fruits. Think rosehips, apples, strawberries, raspberries, plums and cherries, and the dry fruits of Spiraea and Acaena. These fruits are all made of the same building blocks, but they differ in which parts are fleshy, how many carpels are in each flower, whether they're joined or separate, and whether the carpels open to release the seeds or not.
England should comfortably beat Georgia tomorrow, but then they face Scotland. Again, history is important: Prestonpans, Culloden. Why is it that geographic proximity seems to cause the most intense rivalry?