﻿2 26 BOTANICAL GAZETTE [march 



upon the structures of the embryo sac oi Monotropa uniflora. Most of the 

 observations were made upon material in the living condition. The interval 

 between pollination and fertilization is dependent upon temperature. Under 

 normal conditions fertilization takes place about five days after pollination, 



w 



and on the same day or the next day from two to four cells are found in 

 the endosperm. The fertilized egg elongates and bores its way into the 

 nearest endosperm cell. Seeds ripen in about fifteen days after pollination, 

 Light, atmospheric pressure, and mechanical injury of the ovule or other 

 parts of the plant seem to exert no influence upon fertilization and subsequent 

 phenomena, but the structures of the embryo sac are very sensitive to 

 temperature. At 28° C. fertilization and subsequent phenomena proceed as 

 at room temperature, and at 30"" C. the endosperm nucleus can still divide; 

 but at 31-32^ C. fertilization can no longer take place, and disturbances are 

 seen, due probably to increased osmotic pressure of the sac. By lowering 

 the temperature the interval between pollination is lengthened, and at 

 8-10' C. fertilization is prevented. The experiments show that the polar 

 nuclei may fuse in the absence of pollination, but that the fusion may be 

 hastened or regulated by pollination ; in normal cases the fusion occurs 

 about five days after pollination, but when pollination is prevented, the 

 interval may be prolonged to ten days or even longer. The three small 

 antipodal cells disintegrate after fertilization, but when fertilization is pre- 

 vented artificially, they may enlarge enormously and fill a considerable 

 portion of the sac. At a temperature of 30" C. or higher there is no growth 

 of the antipodals. Development of the endosperm can be induced experi- 

 mentally in the absence of fertilization. When pollination is prevented, 

 many of the ovules die within two or three weeks, but in others the sac 

 enlarges and becomes filled with endosperm. In such cases the zg^ appara- 

 tus and often the antipodals collapse. This development of the endosperm 

 was observed in 3 to 5 per cent, of the ovules, but at a temperature of 

 28'' C, or by using osmotic solutions, endosperm was developed by 6 to 

 12 per cent, of the seeds. The writer believes that the endosperm nucleus 

 has a stronger tendency toward parthenogenetic development than the egg. 



The full paper with plates will be awaited w^th interest.— C. J. Chamber- 

 lain. 



In the January number of the Revue General de Botanzgiie, M. Luigi 

 Macchiati announces his complete confirmation of the observation of Friedel 

 (1901) that photosynthesis occurs /// vitro, without the intervention of liv- 

 ing protoplasm, by the action of an enzyme which utilizes the solar energy in 

 the presence of chlorophyll. Several physiologists, including Macchiati and 

 Friedel himself, repeated Friedel's earlier experiments with negative results. 

 Now, however, Macchiati has obtained positive evidence, which he outlines, 

 pending the publication of a more extended paper. Briefly his process and 

 results are these : 



