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Tough,
simple Male A recent walk beside the river and through local woodland brought home to me how high summer has truly arrived - everywhere very quiet, as birds finish breeding and go into the moult; trees heavy with dark green foliage; and the wonderful variety of spring flowers giving way to great tangles of vegetation where only the tall and tough can survive. This season's predominant colours seem to be blues and purples - the silvery blue spires of Bellflower and the intense purple-blue clumps of Meadow Crane's-bill. However, our garden experts have taught us that there's more to a well-designed garden than colour. What about structure and texture? Ask those questions as you walk through broad-leaved woodland in July and the real stars of the show are obvious. Ferns, with their graceful arching fronds and variety of patterns and textures, add both beauty and mystery to the summer woods. In our local woods you can find specimens of Hart's-tongue, Male fern, Lady-fern, Buckler and Shield ferns, and they are all fascinating to study more closely. Look at the underside of a frond and you will see myriads of slightly raised structures forming patterns of spots or lines. These are called sori, and, in several cases, have given rise to the plant's name. Hart's-tongue, with its solid shiny green leaves has obviously been named for its shape, hence some of its local names too - long leaf, horse tongue and Christ's hair - but in some places it's known as buttonholes - a reference to its horizontal slit-shaped sori. Male and Lady ferns are named for their character - Lady, delicate and tender, Male more robust, or, as one (lady) botanist described it to me - tough and simple! But what about Buckler and Shield? Well, you've only to look at those circular raised sori to find the answer. The sori are vital for the botanist, in identifying the different species and sub-species: they're also pretty important to the plant itself, as they form the first stage in a complex and intriguing reproductive process. Each sorus contains a cluster of spore capsules and each of these holds over a thousand spores. How's that for reproductive potential? The capsules are protected in the sori by a papery cover until the spores are ripe whereupon the cover dries out, shrinks and finally snaps, propelling the spores into the air to be wafted off to a new space. If conditions are right, a new plant grows but - and here's the surprising bit -it's not at all like the parent. It's a tiny heart-shaped flap-like structure and, unlike its parent, it has both male and female organs, thus giving it a chance for the Darwinian advantages of cross-fertilisation. It needs water to facilitate the process - a nice rain shower or, occasionally, the slime from a passing slug - an unlikely Cupid - will enable an egg and sperm to meet and a new fern to start the long process of growing to maturity. However surprising this double cycle may seem to us, it's clearly served ferns well enough - they were here before our more familiar flowering plants had evolved and, hopefully, will continue to flourish and delight us. [Back] |