Poring over spores on the brambles
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Version 0 of 1. On a grey, foggy, afternoon, diseased bramble leaves present some of the brightest splashes of colour. Most are disfigured with purple patches, symptoms of bramble rust that must be familiar to anyone who has ever picked blackberries. Older, moribund leaves have turned a lurid shade of yellow, stained with abstract crimson patterns. When I turn over a leaf my fingers become stained with powdery purple spores erupting through its surface. I pick it, for a closer look, later. Rust fungi do not have the obvious attractions of toadstools but what they lack in aesthetic appeal is compensated for by the intricacy of annual life cycles that sometimes alternate between different plant hosts and involve production of several kinds of spore. Species that attack crops present plant pathologists with one of the greatest challenges to food security, but all have fascinated generations of naturalists. One such naturalist was Mordecai Cubitt Cooke, whose pioneering book Rust, Smut, Mildew, & Mould, which was first published in 1865, I discovered in an antiquarian bookshop. Cooke extolled the joys to be had from the microscopic study of plant diseases, using lyrical prose that today would probably draw parody but which was immensely attractive to Victorian amateur microscopists beguiled by the possibility that they too might contribute to the understanding of these cryptic organisms. His book ran to four editions, updated to keep pace with mycological discoveries, some made by his readers. Infected with Cooke’s enthusiasm, I followed his instructions for examining the bramble leaf under a microscope. Known in Cooke’s day as bramble brand, the disease was then poorly understood but I could easily identify the distinctive club-shaped spores from his description and illustration. “Everyone who possesses a love of the marvellous ought to have a microscope,” wrote Cooke on the opening page of his book, written in an age before broadcast media turned active enquirers into passive viewers during long winter evenings. It’s still good advice. Twitter: @seymourdaily |