No. 2, September, 1020] HORTICULTURE 231 



excessive salt concentration. Alkali content of the soil may ultimately reach a harmful con- 

 centration where irrigation water is applied that contains only a relatively low concentration 

 of alkali salts. The rate of salt accumulation varies in different soils, depending on (1) the 

 composition of the water, (2) the amounts applied, and (3) the freedom with which it pene- 

 trates into the subsoil. There exists a close relationship between the composition of irri- 

 gation water and the accumulation of alkali salts, and the condition of the citrus trees. — A. 

 R. C. Haas. 



L752. Laffeb, II. E. The pruning of the vine. Agric. Gaz. New South Wales 31: 47-55, 

 121-126. Fig. 5-13. 1920. (Continued from: Ibid. 30: 808. 1919.] 



1753. Larue, P. Taille du Pineau a Chablis. [Pruning the Chablis Pineau grape.] 

 Rev. Vitic. 52:7-11. 2 fig. 1920. 



1754. Lewis, C. I., A. E. Murneek, and C. C. Cate. Pear harvesting and storage investi- 

 gations in Rogue River Valley. (Second report.) Orgeon Agric. Exp. Sta. Bull. 162: 1-39. 

 Fig. 1- IB. 1919. Fruits of Bartlett pears increase gradually in size, but at an accelerated 

 rate in volume, throughout the growing season, apparently independently of climatic or 

 cultural conditions. A distinct correlation appears to exist between the degree of maturity 

 of Bartlett pears and the resistance offered by the cortical and epidermal tissues to pressure 

 as measured by the amount of pressure required to force into them a ^5 inch steel ball up to 

 one half its diameter. There is no direct relationship between such resistance to pressure and 

 the diameter of the fruit. Storage investigations showed that, in the case of Bartlett pears, 

 the size of the fruit was not a factor in time of ripening or decay. Fruits picked during the 

 middle or latter part of the season of development kept longer than those picked early, and 

 were superior in quality, and those picked exceptionally late were superior both in keeping 

 and eating qualities. No difference in rate of maturity in storage was noted when a change 

 in temperature of 10° to 15°F. was registered, provided the same approximate percentage of 

 humidity was maintained. In the case of Bosc pears it was determined that both relatively 

 high temperature with low humidity and low temperature with high humidity were harmful 

 to proper ripening, that fruit picked very early in the season must be allowed to ripen partially 

 before being placed at low temperatures, and that at least two weeks should elapse before 

 putting the fruit into cold storage, though this time may be decreased under conditions of 

 higher humidity. — E. J. Kraus. 



1755. Lodian, L. Strange things to eat. Sci. Amer. 122: 302, 312, 314. 9 fig. 1920 — 

 A popular enumeration of seeds, bulbs and flowers used by cosmopolitan New York City for 

 food, which are out of the ordinary for that region. — Chas. H. Otis. 



1756. Macottn, W. T. The commercial varieties of apples of Canada and the United States. 

 Fruit Growers' Assoc. Nova Scotia Ann. Rept. 55: 119-137. 1919. 



1757. Manaresi, A. Sulla biologia fiorale del pesco. 2a nota. [On the floral biology of 

 the peach. 2nd note.] Staz. Sperim. Agrarie Italiane 52: 42-67. 1919.— A study of the 

 structure of the flower, its various parts and functions in a large number of varieties. Sta- 

 tistical study of the size of the various types of buds in different varieties, of the shape of the 

 flower as connected with the character and adherence of the stone; the classification of the 

 varieties into two groups characterized by a campanulaceous perianth in one case and a 

 rosaceous perianth in the other case. A study of the flowering period and its daily perio- 

 dicity; the action of meteorological conditions upon the functions and longevity of the various 

 floral parts; form and dimension of pollen, and its relation to varietal classification. Study 

 of the germination of the pollen of seventy varieties, of the size of the pollen tube, its morpho- 

 logical characteristics and speed of germination when tested in solutions of the following 

 sugars: lactose, saccharose, maltose, glucose, laevulose, and galactose in solutions ranging in 

 concentrations from 5 to 30 per cent. Distinct differences were obtained with the different 

 sugars, saccharose being the most generally useful in concentrations ranging from 10 to 20 per 



BOTANICAL ABSTRACTS, VOL. V, NO. 2 



