1902] CURRENT LITERATURE 313 



\ 



I 



I 

 I 



^ 



^ 



zation" is not a purely chemical process. Winkler suggests that bastards 

 might be produced by chemical fertilization. Strasburger regards this as 

 impossible and believes that the essence of fertilization lies in the union of 

 organized elements. The view that the epigenesis of form is only an expres- 

 sion of the epigenesis of chemical power might, perhaps, appeal more to 

 the physiologist than to the morphologist who has studied more deeply the 

 developmental history of organisms. No doubt morphologists busied them- 

 selves too long with a one-sided mechanical view of ontogeny. If the chemi- 

 cal theory does not in the same way go beyond the mark, the two views 

 united should be useful in extending our knowledge. — C, J. Chamberlain. 



In a rather extended paper Van Tieghem* indicates his ideas of taxonomy 

 as developed in the light particularly of researches upon ovular anatomy and 

 morphology. For some time systematists have been familiar with the revolu- 

 tionary attitude of the dean of French botanists, and his long successions of 

 new families of plants have been duly noted in the bibliographies, but have 

 not produced any general modification, either in Germany or America, of the 

 current taxonomic sequences. Indeed, it would be a somewhat serious matter 

 if it became necessary to rearrange herbaria upon the Van Tieghem system, 

 since it is a complete bouleversement of the Engler-Prantl order, which has 

 recently pretty generally superseded the old Benthamian arrangement of the 

 families. 



The object of M. Van Tieghem is apparently to develop a new classifica- 

 tion founded upon the methods of reproduction in plants; how successful he 

 has been must be left to the consensus of botanists to determine. The 

 reviewer, after a careful examination, finds himself unable to follow Van 

 Tieghem either in the general plan of his system or in the detail of its elab- 

 oration. To go over the points one by one would be impossible in a brief 

 review, and I shall select but a couple of examples for criticism, believing 

 that they will illustrate the system as a whole. 



Van Tieghem begins by dividing the plant kingdom into two subking- 

 doms which he calls Diodee's or Prothalle^s and Adiodeis or Aprothalle^s, 

 One finds that in the Adiode6s, which is the lower group, types from Proto- 

 coccus to Polytrichum are included. Here too are such forms as Vaucheria 

 and Fucus- In the Diode^s are the ferns and flowering plants. The dis- 

 tinction between the two subkingdoms according to Van Tieghem is the pro- 

 duction of the eggs directly upon the "plant-body" — naissance directement 

 sur le corps aduite — in the Adiodeis, and upon a special rudimentary body 

 the prothallium — in the Diode^s. Van Tieghem characterizes the former 

 as '* direct" formation of the ^^^^ and the latter as** indirect." Such a clas- 

 sification ignores the homologies established by Hofmeister 





an 



< 



* ''Van Tieghem, Ph., L'oeuf des plantes, consider^ comme base de leur clas- 



sification. Ann. Sci. Nat. Bot. VHI. 14: 213-390. 1901. 





