At ordinary times, the Gorse is a closed flower, provided, however, with a little step or platform on which a Bee can alight. As soon as an industrious honey-seeker has settled down on this little floral porch, his pressure causes the entire corolla of the flower to spring violently open and shower him with pollen. A Gorse flower which has thus unburdened itself at once hangs down dejectedly and is no longer the object of insect regard. The Lupine and the English Bird’s-Foot Trefoil entertain their tiny visitors in a similiar way.
There are two different arrangements of sexual organs in the Primrose. One variety is provided with long stamens and a short pistil. The other has the reverse combination of short stamens and a long pistil. In both cases, the nectar is in a pit at the bottom of the flower. As long as an insect visits short-stamened flowers, he collects pollen on the upper part of his proboscis. Happening to enter a short-pistiled flower, this portion of his drinking tube is now opposite the female organ and fertilizes it. In the same way, the insect’s feet gather pollen from the long-stamened flowers and deposit it in the long-pistiled variety. By such involved methods does this particular flower make sure of fertilization.
Sage flowers have only two stamens but they do the work of forty. Using their power of movement, they bend forward and deliberately embrace a bee as soon as he enters their chamber. They do not release him until he is covered with their yellow pollen.
The English Figwort has adopted repulsive methods of entertainment. It has contrived to make itself look like and give forth the odour of decaying meat, because it knows that it will thereby attract certain Wasps. The South African Stapelia does the same thing with the idea of alluring Carrion Flies. Still another imitator of similiar kind is the pale-green Carrion Flower whose visitor is the Blow Fly.
When in repose, the stamens of the pink-white Mountain Laurel (Kalmia Latifolia) curve so that their anthers or pollen-bags fit into corresponding pits or depressions in the petals. When a Bumble Bee happens along and blunders among these delicate organs, the stamens spring up and shower his back with pollen.
Everyone is familiar with the purple barber pole of the Cuckoo Pint which stands up straight out of a pulpit-shaped leaf. This barber pole is the upper end of a fertilizing device of marvelous efficiency.
Down in the shelter of the cup-shaped leaf, the pole is covered with primitive male flowers, without petals or without sepals, in fact, nothing more than simple stamens. Below them are rudimentary female flowers consisting of unadorned pistils. Certain Midges and Flies are attracted into the leaf cavity of the plant by the store of sweets at its bottom. Traveling down the pole, these would-be feasters readily pass the guardian hairs just above the stamens, pass the stamens themselves and unintentionally fertilize the pistils with pollen they have picked up on other marauding expeditions. Having partaken of honey, the Flies seek to escape, but now find the way barred by the down-pointing hairs which have bristled up in a militant manner. The insects must stay until the plant decides to release them, which is never until the stamens have ripened and showered them with a fresh supply of pollen.
The Orchids are among the most beautiful and extraordinary flowers in the world. Their noteworthy development has come about through their efforts to secure abundant and efficient insect fertilization. So certain are their methods that they ordinarily do not require the services of more than one stamen.
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.