108 



An account is given (pp. 66—88) of the mitoses of the arche- 

 sporium and embryo-sac, based mainly on a study of Asperala 

 montana, Crucianella macrostachya and C. gilanica. The em- 

 bryo-sac mother-cell contains a large number of coarse fibers 

 which persist through the prophases of the first division and 

 are regarded as currents of kinoplasm and not, therefore, as 

 a rearrangement of the reticulum. As in the higher plants, 

 the spindle is of multipolar origin, no centrosomes are present, 

 and the maturation divisions are normal. In Crucianella the 

 interesting discovery of ten as the reduced number of chromo- 

 somes was made. 



The behavior of the pollen tube in Diodia and Richardsonia is 

 given in much detail. After leaving the pistil the tube may 

 make its way either between and in a direction at right angles to 

 the columnar epidermal cells that are in the neighborhood of the 

 micropyle {Richardsonia pilosa and Diodia teres), or, it may extend 

 to the surface of the ovule and travel upon it to the micropyle 

 {Diodia Virginiand). Professor Lloyd concludes that chemot- 

 ropism is the important factor in determining the later direction 

 of growth of the pollen tube, that the distribution of the irri- 

 tant is a differential one, and, finally, he suggests that the syner- 

 gidae or possibly the ovum may be the source of the stimulant. 

 The pollen tube does not as a rule act unfavorably on the cells 

 with which it comes into contact except in so far as injury may 

 arise from the pressure that it may exert upon them. — W. A. 

 Cannon. 



A University Text-book of Botany* 



With nearly 400 pages devoted to the botanical system out of 

 a total of 550, the present work would seem to represent a work 

 on systematic botany and it must be interpreted mainly from that 

 standpoint, although it is written by one who has never been 

 classed as a systematic botanist. The work as a text-book must 

 most naturally be compared or contrasted with the most recent 

 emanation from the Germans familiarly known in our laboratories 

 as the " Bonn text-book," for it is evidently this work that the 



*A University Text-Book of Botany, by Douglas Houghton Campbell, Ph.D. 

 xv -|- 579 PP- PI- 1-15 -^rf- J -193- New York, Macmillan & Co. (Price, $4.00. ) 



