1760 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. 



„,,,„,„ • J c- J Zamia floridana, DC. and Z. piunila L., 



Webber, n. J. Spermatogenesis and Fecunda- -' _ ' _ ^ ' 



tion of Zamia. U. S. Dept. of Agriculture, two Florida species which were hereto- 

 Bureau of Plant Industry. Bull. No. 2, pp. j ^^.^ incorrectly referred to Z. mtegrifolia 

 i-ioo, pis. 1-7, 1901. ■' '^ -' 



Jacq., furnished material for this work. 



Cones retain their vitality for several days — often more than a week after being 

 removed from the plant, and so can be sent for a considerable distance and still 

 be in perfect condition for study. Flemming's stronger solution was used for 

 fixing archegonia, but for the pollen tube structures this solution was diluted 

 with about four times its volume of water. It was not found necessary to bleach 

 with peroxyde of hydrogen. The safranin-gentian violet-orange combination 

 was the most successful stain. The spermatozoids were kept alive in a sugar 

 solution, and their movements were carefully studied. 



The most interesting portion of the paper is that which deals with the ble- 

 pharoplasts. These first make their appearance in the body cell (central cell) 

 and are formed de novo from the cytoplasm. They are at first very small, being 

 scarcely more than points where a few radiating filaments converge, but as they 

 increase in size, a surrounding membrane and vacuolated contents can be dis- 

 tinguished. Shortly before the division of the body cell, the nucleus passes 

 through a synapsis stage which is regarded as normal and not at all due to re- 

 agents. The spindle .is developed while the nuclear membrane is still intact, 

 and is apparently entirely of nuclear origin and none of the fibers have any con- 

 nection with the blepharoplasts. During the equatorial plate stage, the blephar- 

 oplasts break up, and in an early anaphase the contents have entirely disap- 

 peared, while the outer membrane soon breaks up into numerous granules which, 

 during the formation of the cell plate, begin to fuse, thus forming the cilia-bear- 

 ing band. At first, the band is located in the cytoplasm midway between the 

 nucleus and the periphery of the cell, but it ultimately moves out and becomes 

 appressed against the plasma membrane, where it forms a helicoid spiral of from 

 five to six turns. The entire spermatid is metamorphosed into a spermatozoid, 

 there being no differentiation of a spermatozoid within a mother cell. The 

 mature spermatozoids are the largest known in any plant or animal, being visible 

 to the naked eye. They move mainly by means of cilia, but there is also an 

 amoeboid movement of the spiral end. 



In fertilization the entire spermatozoid enters the ^gg-, but the nucleus soon 

 slips out from the cytoplasmic sheath, leaving the ciliferous band in the upper 

 part of the egg. The nucleus moves on and fuses with the egg nucleus. There 

 is a fusion of cytoplasm with cytoplasm and nucleus with nucleus. 



Prof. Webber still believes that the blepharoplast is not the homologue of 

 the centrosphere or centrosome. c. j. c. 



