In one variety, the English Spotted Orchid, the pollen is enclosed in two sacks or bags provided with long stems. These sacs are lodged in special cavities near the pistil in such a manner that the sticky ends of the stems come in contact with the head of a nectar-sucking Bee. They adhere firmly. When he departs he has two bulbous ornaments for a crest. At first they stand erect, but as he flies, the air dries them and they incline forward on curved stems. When he is ready for his next cup of honey, they are hanging down in front of his eyes like a new kind of pawnbroker’s sign. It is no mere happenstance that in this new position the pollen sacs are deposited on the stigma of the second flower’s pistil. By such ingenious marriage customs, the Orchids have become a dominant family in plantdom. They are in the ascendency even in the tropics, where their frail bodies have to compete with hosts of plants which are physically much more vigorous. Between the Yucca and the Yucca Moth exists a wonderful life-long partnership for the purpose of furthering the reproductive processes of both. Surely, Nature moves in mysterious ways. Insects are the chief marriage priests of the plant world, but in the tropics they are aided and abetted by Humming-Birds, Sun-Birds and Lories, which are all provided with long, tubular tongues. Most insects act as if they were unaware of the important place they occupy in plant hymeneals. So intent are they on their honey-gathering that they become covered from head to foot with pollen without appearing to notice it. Yet in a few instances, the Bees not only recognize that they have been pressed into the plant’s messenger service, but by underhand methods seek the rewards of labour without giving adequate return. They have learned how to cut a hole in the calyx tube of the Bean and the Scarlet Runner, and get at the precious honey by short cut. If all Bees and other fertilizing insects should master this trick, the flowers would have to wear defensive armour or perish. Pollen to be effective must remain dry. The plants have perfected many devices to shield it from moisture. Frequently, the flowers hang so that their petals act as tiny umbrellas for it. Others wear rainy day hoods, and practically all close when the night mists are abroad. The necessity for dry pollen obtains even among the water plants. If they are surface-floaters like the Pond Lily or the Victoria Regia, it is easy enough for them to thrust their blossoms up into the air, where they may be as dry as though they were on land. The sub-aqueous plants have a harder problem and are sometimes driven to developing their flowers in leaf air-chambers below the surface. The Water Chestnut (_Trapa Natans_) makes itself buoyant at its flowering period with generated air and rises en masse to the surface. After fertilization, it sinks again to its sub-aqueous quiet.