A NOTE ON FRUITING APPLE SPUR PHYLLOTAXY

The writer was considerably interested in HUBBELL'S paper' in the April, 1934, issue of PLANT PHYSIOLOGY on blind wood in roses, particularly in his observation that the fruitful shoots of the hybrid tea rose, Mme. Butterfly, averaged 7.3 nodes per shoot, while the unfruitful shoots averaged 4.9 nodes per shoot. In 1927 while at Oregon State College a nearly identical observation was recorded with respect to apple cluster bases. Usually the fruiting spurs showed 8 or 10 leaves below the terminal fruit stalks on the cluster base; 8 leaves were present in a phyllotaxy of 3, or 10 leaves in a phyllotaxy of 2. Spurs unfolding small numbers of leaves were seldom fruiting. The rule is not invariable, but the majority of cases adhere closely to it. Spurs of the Starking apple in the University of Wisconsin orchards this spring showed the arrangement beautifully. Incidentally, 8 nodes or leaflets on shoots of hybrid tea roses usually represent one complete phyllotaxy in 3 arrangement. In the apple in strong fruiting spurs, one complete 1 HUBBELL, D. S. Causes of blind wood in roses. Plant Physiol. 9: 261-283. 1934. 858