The Flower of the Morning

The morning glory, Ipomoea and related genera, is a twining vine bearing wide trumpet flowers that open with the dawn and wither by the afternoon of the same day. That brief glory is the root of its symbolism everywhere it grows: the flower stands for the fleeting nature of life, love and beauty, for a single day's brilliance, and for the mortality that its brevity makes plain. In Japan the morning glory, asagao, became a beloved subject of Edo-period horticulture and poetry, its short-lived bloom a favourite emblem of the transient and of a love that cannot last.

Morning glories have also been an important subject of modern plant science: their reliable daily opening and closing made them classic model organisms for studying photoperiodism and the plant circadian clock, the internal biological rhythm that lets a plant anticipate dawn rather than simply react to light, research that has shaped a good deal of what is understood today about how plants tell time. Several Ipomoea species are also vigorous enough to be classed as serious agricultural weeds in parts of the world, notably in cotton and soybean fields in the southern United States, a plain modern agronomic fact sitting oddly beside the flower's delicate reputation in Japanese poetry.