Journal of Applied Microscopy. 603 



CURRENT BOTANICAL LITERATURE. 



Charles J. Chamberlain. 



Books for review and separates of papers on botanical subjects should be sent to 



Charles J. Chamberlain, University of Chicago, 



Chicago, 111. 



REVIEWS. 



Davis, B.M. The Spore-Mother-Cell of Antho- Anthoceros is a remarkably favorable 

 ceros. Bot. Gaz. 28: 89-109, pi. 9-10, form for studying a close series of stages 



in the development of spores from em- 

 bryonic tissue, since in a single longitudinal section of a sporogonium one finds 

 the archesporium passing by insensible gradations into the mother-cell which 

 furnishes an equally close series leading up to the mature spore. 



The chloroplasts were found in the archesporium, these structures not being 

 differentiated until the mother-cell stage was reached. The chloroplast first 

 appears as a slightly denser portion of the protoplasm, but the first clear proof 

 of its presence is the sharp staining of starch grains in its interior. As the chloro- 

 plast develops, its outline becomes distinct, but no surrounding membrane can be 

 distinguished. The division is by simple constriction, the two new chloroplasts 

 passing to opposite poles of the elongated spore-mother-cell, where they again 

 divide. After its first appearance, the quantity of starch steadily increases until 

 in the oldest spore-mother-cells the chloroplast seems littls more than a storage 

 vesicle of starch. 



The nucleus of the spore-mother-cell passes into synapsis soon after the 

 first division of the chloroplast. This phenomenon is not regarded as an arti- 

 fact. The spindle of the first division seems to be formed about as described 

 by Mottier (pollen-mother-cells of Lilimti) and Osterhout (spore-mother-cells of 

 Eqiiisetum). After the first division the nucleus passes into a resting stage. 

 The structural features of the second division are identical with those of the first. 

 The number of chromosomes in the antheridium and in the spore-mother-cells 

 is four, and in vegetative cells, eight. The splitting of the chromosomes seems 

 to be longitudinal. 



The mature mother-cell contains four chloroplasts, each with a single nucleus 

 on its anterior side. The walls separating the mother-cell into four spores are 

 derived from films of protoplasm which appear between the chloroplasts. These 

 films are formed by the coalescence of strands of protoplasm which cross the 

 space between the four regions of cell contents. No connection was established 

 between these strands and the spindle fibers. These results do not agree with 

 Farmer's accounts of nuclear division in Pallavacinia, Aneura, Fosso?nbrofiia, 

 and Pellia, but Anthoceros differs so widely from members of the Jungermanni- 

 aceae that the differences need not occasion surprise. 



It would seem to the reviewer that this work, supported by such critical 

 preparations, would have justified Dr. Davis in attacking the permanent organ 

 theory of the chloroplast. However, he promises to make a further examina- 

 tion of this subject. 



The paper is accompanied by two excellent plates. c. j. c. 



