HORTICULTURE. 639 



polliuation " or the removal of pollen from the stigma before fecundation has 

 taken place. This process has been successfully used on several genera of the 

 Compositfe and can be used with all (lowers having reproductive organs too 

 small to be successfully manipulated by the ordinary methods of emasculation. 

 It may also be applied to the stigmas of larger flowers to remove pollen which 

 may have gained access to the stigmas previous to an artificial pollination. 



The author discusses the development of depollinatiou in his plant breeding 

 work, the necessary tools and equipment for depollinatiou and emasculation, 

 the possible origin of hybrids and crosses of composite flowers, and prepara- 

 tion of seed and pollen bearing plants. In giving an account of his work with 

 alfalfa, two methods of depollinating the flowers, by means of a tiny jet of 

 water and by compressed air, are described in detail. Consideration is also 

 given to the growing of breeding plants, raising seed from crosses, crossing 

 large flowered legumes, crossing in large and small numbers, hybridizing 

 species, crossing cultivated varieties on natural species, cross-pollinating 

 clovers, and methods of emasculating and pollinating common flowers. Ref- 

 erences are made to many difficult crosses which the author has performed 

 and the methods used are fully illustrated. 



Recent investigations on the occurrence of parthenogenesis among orchard 

 trees and other fruit-bearing plants, Ewert {Landiv. Jahrb., 38 (1909), A'o. 

 5-6, pp. 767-8S9, figs. 7). — In continuation of the author's previous investiga- 

 tions on flower biology (E. S. R.. 17, p. 1156) and the occurrence of partheno- 

 genesis among fruit trees (E. S. R.. 19, p. 142), an account is given of obser- 

 vations and studies made during the years 1907-8 with api)les. pears, quinces, 

 cherries, peaches, gooseberries, currants, grai^es, strawberries, cucumbers, toma- 

 toes, and hazlenuts, including investigations of single variety orchard plantings 

 and of the influence of seeds upon the development of fruit and upon the nutri- 

 tion processes in the plant. The methods employed and resulis secured by 

 other investigators along this line are compared with those of the author. The 

 report concludes with discussions relative to the occurrence and probable value 

 of fiowerless apples and the nature of parthenogenesis. 



The author is led to conclude from his own investigations, as well as from 

 the results secured bj' others, that many so-called cases of self-fertilization, 

 particularly among apples and pears, are in reality due to parthfuogenesis and 

 that in varieties where this occurs cross-pollination is unnecessary. The occur- 

 rence of parthenogenetic fruit appears to be a varietal characteristic, the 

 general factors of growth being of only secondary importance in producing 

 such fruit. The opinion is advanced that not only must considerable more data 

 be accumulated but more satisfactory methods of investigations must be worked 

 out in order to make our knowledge of this subject of value in practical fruit 

 culture. 



The resistance of plants to frost (GnnL Chroii.. S. ser., -}7 (1910), .Vo. 1Z08, 

 pp. 120. 121). — A review of our in-esent knowledge relative to the means by 

 which the more resistant species of plants protect themselves from injury by 

 frost. 



Report of horticulturist, C. C. Newman (South Carolina Sta. Rpt. 1901, pp. 

 16-22). — A progress report of cultural experiments with fruits, nuts, and vege- 

 tables, including a table showing that the nuts from some Gl seedling pecans 

 varied in size, from 51 to 192 making a pound. 



Report of horticulturist, C. C. Newman (South Caroliiid St a. lipt. I90S. pp. 

 19-22).- — A progress report on cultural and breeding exi»eriments with fruits, 

 nuts, and vegetables. Experiments are being conducted in grafting apples 

 to determine the length of stock and scion suitable for producing the largest 



40512— No. 7—10 'i 



