1919] HORTICULTURE. 445 



1909 and continued through 1917. The results secured each season are here re- 

 ported in detail. A summary of the results in general has been previously noted 

 (B. S. R., 41, p. 145). 



The culture of peach trees in the German climate, F. Rudolph {Die Freiland- 

 ::ucht des Vflrsiclibaumes im deutschen Klima. Frank fort-on-the-Oder: Tro- 

 icitsch d Son, 1918, 2. cd., rev. and enl., pp. X+8^, figs. 35). — A practical trea- 

 tise on peach culture in Germany. 



Relation of weather to fruitfulness in the plum, M. J. Doesey {Jour. Agr. 

 Research [U. S.], 17 {1919), No. 3, pp. 103-126, i)ls. 3, fig. 1).—A contribution 

 from the Minnesota Experiment Station, giving the results of the author's in- 

 vestigations, together with a review of the literatux'e on related work. The 

 author considers the effect of various weather factors, such as wind, tempera- 

 ture, sunshine, and rain, on the pollination process and fruit setting. 



Summarizing the results of the investigations as a whole, it is concluded that 

 unfavorable weather at blooming time may completely prevent the setting of 

 fruit in the plum, even though there be a full bloom. Rain and low tem- 

 peratures are the most harmful factors, although prolonged strong winds are 

 also important. The greatest damage from wind is due to interference with 

 insect action and, hence, pollination at critical times. Wind pollination is in- 

 sufflcient even under the most favorable conditions. Frosts occur only occa- 

 sionally during bloom and injure the pistil more than pollen. The greatest 

 damage from low temperatures is in the retarding of pollen-tube growth. Other 

 conditions being favorable, cloudiness does not prevent the setting of fruit. 

 Rain prevents pollen dissemination by closing the anthers or by preventing 

 them from opening. It does not burst pollen nor kill it. On account of the 

 adhesive action between stigma and pollen, rain does not completely wash 

 pollen from stigmas. 



The stigma is receptive for 4 to 6 days, and following the active period of 

 secretion the stigmatic cells rapidly disintegrate. The style abscisses in 8 to 

 12 days after bloom. As a result of the rapid disintegration in the stigma 

 and the abscission of the style, a delay in pollination or slow tube grov>'th when 

 the temperature is low renders fertilization uncertain. Tube growth appears 

 to be relatively slow in the plum even under favorable conditions. 



Analysis of the prevailing weather at bloom shows that the weather factor 

 responsible for the status of the setting of fruit may vary from season to 

 season. Both early and late blooming varieties have been affected by un- 

 favorable weather. Practical i-^nedies under orchard conditions do not 

 appear readily available, but since tube growth seems to be the process most 

 directly affected by low temperatures it is suggested that remedial measures 

 should be sought in suitable poUinizers which show the fastest tube growth. 



Tests with unfruitful plum trees, G. Esam {Jour. Agr. [Neiv Zeal.], 18 

 {1919), No. 3, pp. 162-164, fiV- !)• — A series of pruning and girdling experiments 

 was started under the direction of the Is'ew Zealand Department of Agriculture 

 to determine the cause for the failure of plum trees to set fruit on some of 

 the heavier land in the Hawke's Bay district. The results to date point to 

 cross-pollination as an important factor in securing a good crop of plums. The 

 experiments are to be continued. 



Experiments with varieties of gooseberries, currants, and black currants, 

 N. EsBjERG {Tidsskr. Planteavl, 26 {1919), No. 1, pp. 5.2-79).— The results for 

 the period 1911-1917 are given of a variety exiierlment started in 1909 at the 

 experiment station at Spangsbjerg, near Esbjerg, Denmark. 



A commercially new blueberry, G. E. Mukkell {Jour. Heredity, 10 {1919), 

 No. 6, pp. 271-275, figs. 3)~ — The author describes a small blueberry plantation 

 in northwestern Florida that was established from wild native plants, pos- 



