1919] FORESTRY. 653 



525 per cent over that of unpulped seed. A larger and more sturdy seedling 

 tree was obtained for transplanting than when the pulp was not removed. It 

 is believed that in commercial plantings the removal of the pulp from the seeds 

 will increase the percentage of germination by at least 200 per cent, thus pro- 

 ducing 40,000 more seedling trees to each acre of seed bed. The increased 

 germination and the well-developed trees that result will repay many times the 

 cost of the labor involved. 



On the origin of chicle with descriptions of two new species of Achras, 

 H. PiTTiER {Jour. Wash. Acad. Sci., 9 {1919), No. 15, pp. //Si-Z/SS).— Investiga- 

 tions conducted by the author indicate that chicle, which is commonly supposed 

 to be the product of the sapodilla or naseberry tree {Achras zapota), is in 

 reality the product of several species belonging possibly to more than one 

 genus of the Sapotacete. Two new species of Acliras. A. chicle and A. calcicola, 

 are. here described. 



The European elder (Sambucus nigra), M. Degli Atti {Ann. R. Scuola Sup. 

 Agr. Portici, 2. ser., 14 {1916-17), pp. IS). — An account of the European elder 

 and its economic uses, including a list of consulted literature. 



The strawberry tree and its utilization, F. La Marca {II CorhezsoJo e la 

 Sua Utilizzasione. Casale Monfcrrato: ]\Iarescalchi Bros., 1914, PP- VIII-\-105, 

 figs. 4). — An account of the strawberry tree {Arbutus uncdo), its importance 

 to Italian agriculture, and its industrial utilization. 



Variation in Hevea brasiliensis, S. Whitby {Ann. Bat. [London], 33 {1919), 

 No. 181, pp. 313-321, fig. i).— Results are given of observations in the Federated 

 Malay States, which were made to determine the extent to which variation 

 occurs in the amount of rubber yielded by individual trees of H. brasiliensis 

 of the same age and growing under the same conditions, and also as to the 

 possible correlation between the yield of rubber and the girth of the trunk. 

 In addition to data on the above phases, the observations made afford informa- 

 tion relative to the extent of variation in the rubber content of the latex of 

 individual trees and other peculiarities observed in connection with the study. 



The data as a whole indicate that there is a comparative constancy of the 

 yield from individual trees. A tree which was seen to be a high yielder at one 

 time could be relied upon to give a high yield at all times. The marked 

 variation in rubber yield between different trees examined suggests the great 

 possibilities of seed selection in improving rubber yields. The data secured 

 also indicate that the extent of variation on a normal tapping area may be 

 such that it is quite impermis'sible to assume that small groups of trees in the 

 tapping area will have the same yielding capacity as similar small groups in 

 the same area. The girth data secured indicate that although there is a 

 definite positive correlation between yields and girth the extent of the correla- 

 tion is not sufficient to justify very much emphasis being placed on girth when 

 selecting trees for thinning out. 



Certain peculiarities were observed in the case of particular trees which 

 were also constant over considerable periods of observations, and which may 

 probably be regarded as characteristic of the trees displaying them. In some 

 cases rapid discoloration of the latex appeai'ed to be characteristic of the tree. 

 The latex of other trees showed a tendency to rapid coagulation. A marked 

 cream-straw color seemed to be characteristic of the latex from a small per- 

 centage of trees. 



Selection and thinning, A. A. L. Rutgers {Meded. Alg. Proefsta. Alb. Ver. 

 Rubber planters Oostkust Sumatra, Rubber Ser., No. 17 {1919), pp. 19, pis. 2). — 

 A lecture on this subject in which tlie author presents experimental data to 

 show the importance of selection and thinning as factors in reducing the cost 

 price of raw rubber. 



