1 64 BOTANICAL GAZETTE [august 



the girdle increased; consequently the leaves and twigs at the periphery of the 

 tree, where the majority of the fruit buds were formed, did not show such a 

 great variation. 



The experiment to determine the effect of fertilizers upon fruitfulness was 

 started with i -year-old Rome on Paradise stock. The trees were planted in 

 separate large wooden tubs, half of them filled with Missouri River sand and 

 half with loess soil. The fertilizers were applied just as growth was beginning 

 in the spring. It was found that nitrogen was a very decisive factor in the 

 growth of the tree, the development of fruiting wood, and the formation of 

 blossoms. Phosphorus and potassium, either singly or in combination, had 

 no apparent effects. 



The effect of various systems of soil management was noted upon the 

 concentration of the cell sap. There w r ere 5 different cultural plots: clean 

 cultivation with soy beans or cow peas planted in June; successive crops of 

 corn; seeded to red clover in alternate years; successive cropping of alfalfa; 

 and permanent timothy sod. "These experiments showed conclusively that 

 tillage methods materially affected the sap density of the twigs of the apple 

 tree." The plots ranked in sap concentration of the twigs as follows: alfalfa; 

 timothy and blue grass sod; clover; corn; and clean cultivation with legume 

 cover planted in June. There was very little difference between the clover 

 and corn plots. The trees in the most intensively cultivated areas were 

 considerably the largest. 



A group of 64 one-year-old Delicious trees were used to study the effect 

 of pruning methods upon the formation of fruiting parts. During the first 

 3 years the trees headed at 2 feet made a greater amount of twig growth and 

 produced a larger number of short branches or potential fruiting wood than 

 did the trees headed at 5 feet. Each month a separate 5- to 6-year-old Jonathan 

 tree was subjected to etherization. Very little effect was observed upon the 

 concentration of the sap of the spurs or of the leaves, and the small difference 

 noted appeared to be only temporary. A rather extensive bibliography 

 accompanies the article. — H. W. Richey. 



Phylogeny of seed plants. — At the St. Louis meeting of the American 

 Association, the botanical program included a symposium on the phylogeny 

 of seed plants. The three invitation papers have just been published. The 

 three investigators, working upon different phases of the problem, have shown 

 tendencies in the evolution of the groups with which they are concerned; and 

 while the phylogeny of seed plants still represents a great field for exploration, 

 some results have been obtained, and the problem has been advanced a little 

 toward the distant solution. 



Buchholz 7 has made a comprehensive survey of the development of the 

 embryo and polyembryony in the conifers, much of the subject-matter being 



7 Buchholz, J. T., Embryo development and polyembryony in relation to the 

 phylogeny of conifers. Amer. Jour. Bot. 7:125-145. 1920. 





