1906] CURRENT LITERATURE 157 
paper,*® dealing especially with the behavior of the pollen tube in connection with 
double fertilization in Carpinus Betula. As the previous paper pointed out, this 
form is chalazogamic, and usually has several embryo sacs, which develop caeca 
that penetrate deeply into the chalazal region. The course of the pollen tu 
varies considerably, but usually it enters the embryo sac at the base of the caecum. 
Premature arrival of a pollen tube results in more or less branching and coiling 
about the sacs; and belated pollen tubes also occur, long after fertilization has 
been accomplished. The polar fusion nucleus is in the caecum, and as the 
pollen tube passes it one of the male cells (probably the one farthest from the 
tip) is discharged through a small spur-branch, the other one being discharged 
upon the arrival of the tip in proximity to the egg. Sometimes the spur-branch, 
containing a male cell, develops sufficiently to discharge it for the fertilization of 
the egg of an adjacent embryo sac, in this case triple fusion not occurring. The 
paper also presents a somewhat elaborate comparison of Carpinus and Casua- 
rina, as the basis of a suggestion that the latter genus should be regarded as a 
subfamily of Betulaceae.—J. M. C. 
Dust spray vs. liquid—CranDALL”° reports the results of a very thorough 
study of the comparative merits of the dust spray and the ordinary liquid Bor- 
deaux mixture against the scab and sooty blotch of apple and the codling moth 
and curculio of apple. The dust spray cost about 52 per cent less than the 
liquid spray and there was further gain in the reduced weight of material to be 
transported about in the orchard. On the contrary there seemed to be no differ- 
ence in the thoroughness of application under similar conditions, and the work- 
men were unanimous in considering the liquid spray the least disagreeable one 
to apply. And then as to the final and most important test, that of efficiency, 
RANDALL says, in conclusion, “The results of the experiments are sufficiently 
decisive to warrant the conclusion that dust spray is absolutely ineffective as a 
Preventive of injury from prevailing orchard fungi, and that it is considerably 
less efficient as an insect remedy than is the liquid method of applying arsenites. . 
—E. Meap Wiicox. 
Nature of starch.—In a recent article, FIscHER?! scouts the idea suggested 
y CzarEK? that starch may be a mixture of colloidal and crystalline materials, 
Saying that so far as he knows there is not the slightest evidence for such a belief. 
buti ° BENSON, Marcarer, SANDAY, ELIzABETH, and BERRIDGE, Emity, Contri- 
Uutions to the embryology of the Amentiferae. Part II. Carpinus Betula. Trans. 
inn. Soc. London Bot. II. 7: 37-44. pl. 6. 1906. 
a. C. S., Spraying apples. Relative merits of liquid and dust appli- 
- Bull. Ii. Exp. Stat. 106: 205-242. pl. I-9. figs. I-5- 1906. 
*« Fischer, Huco, Ueber die colloidale Natur des Stirkekérner und ihr Ver- 
halten 8egen Farbstoffe. Beihefte Bot. Cent. 181: 409-432. 1905- 
*? Czapex, F., Biochemie der Pflanzen I. Jena 1904. 
