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The Best Time. To propagate next summer's water-lilies by seed, we begin, of course, With this summer's blooms. Save your experiment for late summer, since flowers are more fertile and receptive then. Select the pollen and the seed parents carefully, keeping in mind just what
Cross Section of Water-Lily
colors and characteristics you want to combine, and making doubly sure that the seed parent you have selected is a fertile one. Many water-lily forms, especially among the varieties, are quite sterile.
Nymphaea odorata and practically all of its varieties-particularly caroliniana, gigantea, minor, rosea, and Luciana-set enough seed to make your experiment worthwhile. This is also true of the species types of N. alba, candida, flava, mexicana, pygmaea, and tetragona; and N. tuberosa is a good bet in its species type and in the rosea and Richardsonii varieties. You may also have fair luck with N. Gladstoniana.
Once you have selected the two forms, you may want to conduct a double experiment. Use one form as the seed parent in the first experiment, the other form as the pollen parent. In the second experiment,
Cross Pollination.
reverse the roles of the two parents. The progeny should be the same in all such cases of reciprocal crosses, but the double effort will give a better chance for success.
Selecting the Seed Parent. Now you must wait for nature to produce for you a set of circumstances favorable for hybridization. First, the bloom which is to be the seed parent must be freshly opened. You can watch a particular bud for a few days and get a pretty good idea when it is going to break into bloom. The day before it does, open the bud, aim off its anthers, and keep the bud covered with cheesecloth to protect it from insects. As the bloom will open naturally in the forenoon, it will be easy to catch. When the bloom opens, you will see a drop of sticky nectar resting precisely in the middle of the stigma. Cover the bloom with cheesecloth to keep out insects and wind-borne pollen, and go get the pollen parent.
Selecting the Pollen Parent and Making the Cross.(Plate 26.) The pollen parent you select must be a However in its second day of blooming. This is absolutely necessary, for the pollen on the flower's anthers is not ripe and cannot be liberated from the anthers until the second day. This flower, too, should have been spotted and protected from stray pollen by a covering of cheesecloth. With tweezers and a pair of manicure scissors, snip off a couple of pollen-laden anthers and place them carefully, pollen-side down, upon the drop of nectar in the chosen seed parent. The cross has now been made, but this is only the first of several intricate steps in hybridization. If you are making a reciprocal cross, use other flowers of the same species, in the same process, with the parental roles reversed.
Protecting the Cross. Take a square of cheesecloth somewhat larger than a man's handkerchief and cover the fertilized bloom to protect it from further fertilization by insects or wind-borne pollen-and wait. And wait and wait and wait. While you are waiting, it might be a good idea to repeat the performance with other blooms as often as you can. As I mentioned before, hardy water-lilies are reluctant to set seed, and your chances of getting seed you can plant are, frankly, fairly poor.
Development of Seeds. In about a week, if the cross has been unsuccessful, seed pod and stem will begin to rot. If the hybridization "took," the seed pod will begin to swell after a couple of weeks, dropping beneath the water as it enlarges. Tie a string around the stem of the seed parent, if you like, so you can pull it up and look at it occasionally. The enlarging seed pod becomes the "fruit" of the water-lily. Two or three days before it is completely ripe, it will rise to the surface again. Finally it will burst, scattering the seeds.
Water-lily seeds are greenish-black or brown, some like tiny apple seeds, others as large as peas and almost globular. Some species and varieties produce only six or seven seeds; others, particularly among the tropical species, produce ten times that many.
If the seeds had not been caught by the cheesecloth you fastened around the pod, they would have been kept afloat by a coating of colorless, mucilaginous matter. This is nature's way of allowing the seed to float away from the mother plant and establish itself in a new, less crowded place where it will have a better chance of survival. The buoy-ant matter dissolves in a few days and the seed drops to the bottom.
Remove the seeds from the cheesecloth and put them in a jar of water. Plant as soon as possible, after coatings have dissolved, but keep seeds in water until you do.
Sowing the Seeds. Fill a shallow pan with finely screened soil, and sift a thin layer of fine sand over it. Sow the seeds and cover with a quarter-inch or less of soil. Saturate the soil with water. Let the pan remain in this condition for a day or two to give the seeds a chance to become thoroughly soaked. Then lower the pan into water, with the seeds 1/4 to 1/2 inch below the surface.
Both the germinating seeds and the seedlings which will develop ham them must be kept in water at a temperature of 70 to 80 degrees. Finally the seedlings appear, looking very much like tender new shoots of grass. Transplant them to 2-inch pots as soon as they have formed their first floating leaves, and keep them submerged in a few inches of water.
Care of Seedlings. From this point on seedlings require not only warm temperature, but also full sun. As they grow, move them to 3-inch pots, then to 4's. Mix a small amount of well-rotted cow manure or other acceptable fertilizer with the potting soil in the 3-inch pots. Fill the 4-inch pots with the regular mixture of soil and fertilizer recommended for adult lilies.
Maintain the plants in this way, moving them into ever larger pots as growth Warrants, until time for planting outdoors in midsummer. The frequent transplantings are necessary. You must supply pots only as large
as the plants need, because inactive submerged soil in a larger container will turn sour. Your seedlings will die if it does.
After you plant outside, wait as patiently as you can for your new hybrid to bloom. Who knows? Perhaps you will have developed a hardy blue water-lily, which does not exist at the present time. If you do, incidentally, please get in touch with me. I will trade you my hat and dog and practically any amount of money I can raise for it.
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