Fig. 62. - Bouncing Bet (Saponaria officinalis).
Some of the pink family have adapted themselves so nearly to the requirements of their chosen guests that they have become unfitted for miscellaneous hospitality. Their blossom-tubes are too long and too narrow to be drained by most insects, and hence many diurnal flowers of the pink family are wholly dependent on butterflies, as some nocturnal species are upon night-moths.
The differences between day- and night-blossoms are beautifully shown by two nearly-related English wild-flowers which have recently come into our fields. They are known to English village children as red and white campion, and to botanists as "corn-cockle' and "evening-lychnis." The red campion [Lychnis githagd) or corn-cockle is already resolving itself into a nuisance in the grain-fields of the Central and Western States. It is rosy-purple, blooms by day, and is fertilized by butterflies. As it is able to attract those insect friends by its bright color alone, it is scentless. A few clearly-drawn, dark lines, running from the edge of the blossom to its centre, are a floral signal-code, telling the butterflies where the nectar which they seek is stored for them, at the bottom of a tube so slender and deep that smaller insects cannot reach down to it. At evening, when the corn-cockle's butterfly friends go to rest, it closes.
The evening-lychnis, which is still somewhat rare in this country, resembles the corn-cockle almost exactly in size, form, and foliage, but is adapted in several interesting ways to its chosen friends, the night-moths. It opens at evening, after remaining partially closed all day, and thus it saves its nectar for its nocturnal guests. That they may more readily see it in the dark fields it glimmers white, and as an additional help to them in finding it the flower is fragrant. Lastly, the evening-lychnis has no lines to indicate the whereabouts of its nectar, for these would be undistinguishable in the dark, and therefore useless.
Fig. 63. - Corn-cockle (Lychnis githago).
(From Annual Report of U. S. Department of Agriculture for 1886).
Whoever tries to gather red currants or strawberries by twilight will find that the red of the fruit, so noticeable by day, now blends undis-tinguishably with the green of the leaves. Long before real darkness comes, the most conspicuous of daytime colors vanishes into the shadows. But a very small object, if it be white, can be seen in the darkest hours of a moonless night. This the night-flowers seem to have learned, for they are all white or pale-yellow.
Their distinguishing charm is their sweetness. Honeysuckle, tuberose, day-lily, stephanotis, night-blooming cereus - what scents for a Sybarite are here! The evening primroses have a delicious fragrance, and the diurnal primroses have none. There are two nocturnal species of silene, both sweet-scented, while the nine or ten diurnal species are all odorless. Even the despised jimson-weed blossom lures the moths by a delicate perfume which is lost directly we gather it, in the rank odor of the broken stem.
The closing time of these night-flowers, like the time of their expansion, is variable. It may depend partly upon the vigor of the plant, its age, and its location. A flower which has been visited and fertilized by moths will probably wilt more quickly than one which has been neglected, and the life of the blossom after daylight will be affected by the temperature and humidity of the morning. Honeysuckles generally keep their fresh looks all day, and with them a fragrance, fainter than that which lured the sphinx-moth, but delicious still. But they do not survive a torrid and glaring noon. Evening-primroses, if the morning is cloudy, or if they grow in the shade, are pretty until midday, but if ardent sunshine reaches them they wilt much earlier, while the day-lilies remain crisp and fragrant till twilight falls again.
Fig. 64A. - A flower-clock - morning. (Tentatively submitted).
Most of the morning hours and flowers are cited from a "clock " compiled for France by Lamarck. They may need some correction for the more southern latitudes of the United States.
Fig. 64B. - A flower-clock - afternoon and evening.
The post-meridial half of the clock is compiled from the author's observations in garden and held in the states of Ohio and New York.
All these flowers, if the moths have failed them, will perhaps be visited and fertilized by the sunshine-loving butterflies.
Linnaeus had the pretty idea of a time-keeping garden, and he drew up for the latitude of Up-sala, in Sweden, a list of plants, arranged according to the time at which their buds expand. This list is the famous "floral clock," "whose wheels," says Jean Paul Richter, "are the sun and earth and whose index figures are flowers".
De Candolle, the French botanist, arranged another floral clock for the vicinity of Paris.
The suggestion has charmed the popular fancy and excited the fertile inventiveness of the penny-a-liners. So every now and then a newspaper article appears, stating exact times for the opening and closing of familiar flowers, and it goes the rounds, giving unsuspecting people to understand that flowers are as punctual as express-trains. But blossoms are not accurate timekeepers. The honeysuckle, as we have seen, takes to itself a margin of four hours, and Linnaeus's floral clock allows for variations of an hour or two in almost every plant. No clock of bloom would serve as a substitute for the mechanical clock of commerce, that soulless autocrat which tyrannizes over our lives and regulates their every detail nowadays. The timekeeping garden, alack-a-day, is for the dwellers in "that sweet isle of rest which is called Avalon," or for the lotos-eaters who have no trains to "make," no board meetings to attend, and no engagements to keep, but who "pass their days in dreamful ease," and "no joy know but calm".