Plant-breeding; comments on the experiments of Nilsson and Burbank . ledge the fact from the regularity of theoccurrence of the combination, without even being ableto guess its cause. Of course, there are also correlations which we mayunderstand or at least believe we understand. In our case,one of these is seen in the broader flower-buds of the (E. brev-istylis, when compared with the CE. Lamarckiana. In thelatter the calyx is extended by the growth of the style, whichpresses the stigma from within against its tip. The calyxbeing thereby elongated, it is only natural that its form be-comes mo
Plant-breeding; comments on the experiments of Nilsson and Burbank . ledge the fact from the regularity of theoccurrence of the combination, without even being ableto guess its cause. Of course, there are also correlations which we mayunderstand or at least believe we understand. In our case,one of these is seen in the broader flower-buds of the (E. brev-istylis, when compared with the CE. Lamarckiana. In thelatter the calyx is extended by the growth of the style, whichpresses the stigma from within against its tip. The calyxbeing thereby elongated, it is only natural that its form be-comes more conical as soon as the long style is absent. Per-haps another mark may be explained in a similar way. Atthe time of the ripening of the seeds the (E. brevistyhs iseasily recognized by its very small pods, containing hardlyany seed. It may be assumed, although a direct proof iswanting, that the elongation and narrowing of the ovarialcavities within the base of the style is an impediment to thegrowth of the pollen-tubes, and thus liindcrs a normal Fig. I02. A. The short-styled Evening-primrose. B-F. Its parent A ilower after the removal of part of its petals and stamens, c. Thesame without petals, d. The same without the tube and the e. Aflowerbud. /. Ripe fruits. B-F. The corresponding parts of the parentspecies, g. Styles, h. Longitudinal section of ovary, i. Transversalsection of base of stvle and calvx-tubc. 325 326 PLANT-BREEDING Exactly similar conclusions may be derived from a dis-cussion of the (Enothera lata, which has often been seen tobe produced from the parent species by a single leap. Thereis even less connection between the various marks by wliichit is distinguished from Lamarcks primrose. It strikes usthrough all the periods of its life as quite another type. Thevery first leaves of the }oung seedlings differ, being broaderand more rounded at the tip. This type of leaves is pre-served during the whole life history, and the roset
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