THE TRAVELLING SEED
Many flower shapes are seemingly transformed as their petals wither and the seed develops — a daisy becomes a powder puff, a sweet pea becomes a narrow pod, a blossom a fat fruit.
All fruit bodies, whether enclosed capsules or embedded in open discs or knobs (such as the daisy family), are designed to nurture and release the seeds when they are mature and conditions are favourable, using three main agents to distribute seed as far as possible from the parent plant. • WIND-dispersed seed may be equipped with wings, plumes or parachutes, or simply be papery light. Or it may be shaken out through openings in the capsule, as in the beautiful censer of the poppy with its fine lattice under the scalloped lid. Only a few at a time will fly out so that at least some will emerge in perfect conditions for survival and germination. • ANIMAL-dispersed seed is usually either designed to be devoured or to adhere to passing fur or clothing. The hitchhikers may be a single seed, as in the case of the forget-me-not burr, or the whole capsule. Here we see nature at its most ingenious; it was the minute hooks of the burdock that inspired Swiss engineer George de Mestral to invent Velcro. • BALLISTICS: a fair number of seed pods are engineered to explode and scatter their seed by force. In most cases, tension builds up as the pod walls dry out; loud reports from the pergola may be the wisteria pods detonating. On a much smaller, quieter scale, the capsules of the violas also split and flick out the slippery little seeds over a considerable distance.