214S Journal of Applied Microscopy 



CURRENT BOTANICAL LITERATURE. 



CHARLES J. CHAMBERLAIN, University of Chicago. 



Books for Review and Separates of Papers on Botanical Subjects should be Sent to Charles J. 

 Chamberlain, University of Chicago, Chicago, 111. 



„^ . nj J T-- T^ • T. This important paper gives a full 



Strasburger, Edward. Ein Beitrag zur Kent- '^ r r o 



niss von Cfratophylhim sjihmersttm und phy- account of the morphology and biology 

 logenetische Erorterungen. Jahrb. f. wiss. ^f CeratophyUicm and also presents a 

 Bot. 37: 477-528, pis. 9-1 1, 1902. . . ^ 



discussion of the factors concerned in 



constructing a natural system of plants. 



Ceratophylliun is pollinated under water. An enormous quantity of pollen is 

 produced, of slightly higher specific gravity than water. The stigma has a pecu- 

 liar shape well adapted to catching the pollen, so that while the loss is great, 

 few ovules fail to produce seeds. Double fertilization was observed and the 

 number of chromosomes — twelve in the gametophyte and twenty-four in the 

 sporophyte — was counted. At the first division of the endosperm nucleus a 

 wall is formed dividing the embryo-sac into two chambers, of which the one 

 nearest the chalaza does not divide again. The other divides transversely, and 

 here also only the one next the micropyle divides again. After a few such divis- 

 ions, the cell remaining next the micropyle gives rise to a small celled tissue. 

 The embryo has no suspensor and no primary root. The embryo so closely 

 resembles that of Nelumbo as described by Lyon, that Strasburger examined 

 Nelm?iho and decided that here also there are two cotyledons and not one, as 

 Lyon claims. 



The philosophical portion of the paper contains a discussion of the criteria 

 of homologies, the role of mutation, external influences, natural selection and 

 recapitulation as they are applied in building up a phylogeny. c. j. c. 



Land, W. J. G. A Morphological Study of Ovules up to the Stage of formation of 



Thuja Botanical Gazette, 36: 249-259, archegonium initials were fixed in the 

 pis. 6-8, 1902. ° 



usual one per cent, chromo-acetic acid 



solution, but for later stages this reagent penetrates too slowly. Carnoy's for- 

 mula was better for fetilization and succeeding stages. Although many fixing 

 agents were tried, none proved entirely satisfactory. Haidenhain's iron alum- 

 ha;matoxylin is recommended for staining, except in case of embryos, where 

 Delafield's haematoxylin followed by orange G gave better results. 



The pollen tube structures and the development of archegonia are described 

 in detail. A definite ventral canal cell is not formed although the nuclear divis- 

 ion takes place. The writer believes that the ventral canal cell is represented, 

 at least by such a nucleus, in all the Coniferales. This nucleus often divides so 

 that the upper end of the archegonium sometimes looks like a young proembryo. 

 The fertilized egg gives rise to eight free nuclei before cell walls begin to be 

 formed. c. j. c. 



