238 EXPERIMENT STATION RECORD. 



may serve as pollinizers for them, and the good effects of cross polli- 

 nation over self-pollination of certain varieties, are discussed at con- 

 siderable length. The results obtained at the station in self and cross 

 pollinating experiments with a number of varieties of different fruits 

 are shown by the aid of ligures. Suggestions are also given regarding 

 the selection, distribution, and planting of trees largely intended as 

 pollinizers in orchards. The advantages of generally mixed plantings 

 is pointed out, and notes are given on pollen distribution by the aid 

 of wind and insects. 



Report of the horticulturist, F. A. Waugh ( Vermont Sta. Rpt. 

 lH99^pp. 1S9-2.'>1, ji(jx. 0). — The subjects here reported upon are the 

 pollination of plums, types of European plums in America, hybrid 

 plums, geography of variation in the genus Prunus in America, and 

 varieties and culture of cherries in Vermont. 



Pollination of plums (pp. 189-209, figs. 2). — This subject has been 

 previously reported upon (E. S. R., 11, p. 347). Further work has 

 strengthened the previous conclusions of the author, that for all prac 

 tical purposes native and eTapanese plums may be considered self- 

 sterile, and that in order to insure fecundation of the blossoms varieties 

 in orchards umst be mixed. In mixing the varieties for purposes of 

 pollination, the following points should be observ^^d: (1) Blossoming- 

 season; (2) mutual affinity; (3) amount of pollen borne, and (4) the 

 value of the pollenizer as a fruit bearer. The time of ))lossoming 

 each year has been found quite uniform. A map with "isophenal" 

 lines is given showing the blossoming season of Wild Goose in differ- 

 ent latitudes for 1899. The mutual affinity of certain well-known 

 varieties as pollenizers for each other is discussed, and a table of vari- 

 eties given with a list of recommended pollenizers for each. Previous 

 work, which demonstrated that insects are necessary to pollination, 

 has been confirmed. The wind, if of any use in cross fertilizing plums, 

 plays a very subordinate part. A list of insects captured on plum 

 blossoms in Oklahoma, Maryland, Iowa, and Vermont is shown. The 

 honeybee performs ])y far the greater part of the pollination. The 

 uselessness of spraying while the ti'ees are in blossom is pointed out. 



The cause of the phenomenon known as June drop was investigated. 

 Careful examination of the sound and fallen fruit showed this trou])le 

 to be due to 3 principal causes: (1) nonpollination; (2) curculio, and 

 (3) the struggle of the fruit on the stem for existenc(\ In the exami- 

 nation of the fallen f I'uit of 9 different varieties only -tl per cent had 

 been fecundated. Nonfecundated fruit usually falls in June, while 

 the larger amount of the fruit attacked by the curculio falls in July. 

 A large mmiber of fruits often set on a single fruit spur. As only a 

 part of these can develop the w^eaker are crowded off", even though 

 well fertilized and free from curculio attacks. In combating the June 

 drop the struggle for existence may be left out of consideration. 



