The Floriculture In Pollination

Many of our present-day hybrid lilies are the result of chance cross-pollination by insects. To rely upon such a procedure is not satisfactory, since it is difficult to foretell what might arise from seed produced in this fashion. The better method is to go about the work of crossing systematically. It is not only a fascinating pastime but may also prove profitable if an outstanding product were secured.

Fundamentally, crossing, or hybridizing, consists of the transfer of viable or living pollen from one flower to the stigma of another. Fertilization takes place after the pollen grain germinates, sends a tube down through the style of the flower to the ovary below where the union takes place, and seed is developed. The preparation of the flowers, either pistillate or staminate, should be thorough. Plants selected for breeding should be vigorous. Consideration should be given to size, color, doubling, and leaf characters, particularly those of viviparous habit. Viviparous plants are those which develop new plants upon floating leaves during their period of growth.

The male, or pollen, parent should be covered during the bud stage to exclude insects and prevent them from depositing foreign pollen on the anthers. For this purpose a thin piece of cheesecloth or a translucent, waterproof bag may be fastened about the bud. The pollen may be collected during the second day after the flower opens, the outer whorl of stamens yielding their pollen first followed in succession by the other whorls. The female, or seed-bearing, parent should be emasculated in the bud stage. This means that all stamens and their superimposed anthers should be removed before the pollen ripens. The operation is performed by a pair of forceps reaching to the base of the stamen and plucking it out. Scissors may also be used.

The emasculation is necessary to prevent self-pollination and should be done even though the stigma, or the receptive female organ, matures before the pollen. Removal of the pollen from the previously prepared flower is accomplished by the use of a camel's-hair brush or by the removal of the anthers with forceps and dragging these into the nectar that collects in the concave stigma when it becomes receptive. The petals and the sepals should be cut off partially; the flower, covered with a bag or cheesecloth tied closely about the base and fastened to a rod support. Enough twine should be left with the support to allow the seed pods to drop into the water and ripen normally. To keep a definite check of the crosses, records should be placed upon labels attached to the stake. The work of hybridizing may be done all through the summer, depending upon the flowering period of the types in question. The seeds mature usually, when the seed pods should be collected, the covering removed, and the pods placed in water to allow total disintegration of the covering and thorough ripening of the seeds.