RECENT LITERATURE. 



E. Strasburger: Histologische Beitrage, Heft. iv. Ueber 

 das Vcrhalten des Pollens und die Befruchtungs — vorgauge 

 bei den Gymnospertnen. SchwiwviSporen , Gameten, pflanzliche 

 Spermatozoiden, tind das Wesen der Befruchiung. — ^Jena, 1892. 



As new facts are brought to light we are constantly obliged to 

 alter our views. Nowhere is this truer than in regard to the 

 structure and functions of the plant-cell. With the marvelous 

 advances made in histological methods, more and more accurate 

 information concerning the minutest details of cell-structure is 

 being brought forward, and this frequently involves material 

 changes in statements hitherto unchallenged. 



The extremel}^ interesting and valuable work before us illus- 

 trates this most strikingly. Probablj^ no living botanist has con- 

 tributed so much to our knowledge of the plant-cell as Stras-» 

 burger, and any statements that come from him on this subject 

 bear the stamp of authorit}-; yet in the present work he has found 

 it necessary to modify very substantially some of his earlier pub- 

 lished statements. The work was evidently inspired largely by 

 the recent remarkable discoveries of Guignard, and to some 

 extent also by important researches by BelajeflF. 



The volume before us is divided into two parts; the first deals 

 with the development of the pollen and the process of fertilization 

 in Gymnosperms; the second, with a comparative study of the 

 zoospores of algae and spermatozoids, and studies in fertilization 

 in various groups of plants. 



Until very recently it was supposed that in the Gymnosperms, 

 with the exception of the Cycads, that but two cells were formed 

 in the ripe pollen-spore, and that the nucleus of the larger one 

 which forms the pollen-tube, was the direct agent in fertilization. 

 Belajefi"* demonstrated that in Taxus it was the smaller cell that 

 represented the fertilizing element, and Strasburger now finds 

 that this is true also in other Gymnosperms. He also finds that 

 in a number of forms examined, e. g., Larix, Picea, Pinus, 

 Ginkgo, that three cells are successively cut off from the body of 



* " Zur Lehre von den Pollenschlauchen der Gymnospermen." Ber. 

 der Deutschen botanischen Gesellschaft — 1891 — Bd. ix, p. 2S0. 



