WATUKAL IIYBEIDS. 1;5;> 



Mr. E. Malinvand has made a special stiulv of the ]iyl)rid 

 mints as found in France. lie conchides that, while these plants 

 hvla'idize constantly, crosses are found in great numbers, yet 

 these crosses are not capable of perpetuating themselves as new 

 races, and the results of any individual cross survive for oidy a 

 few generations. 



It is to be seen from the above that the time has arrived 

 Mdien the plant breeder may look to natural hybrids as one of the 

 most ])rofitable sources of material from which he may draw, and 

 also it is clearly apparent that in the study of distribution and 

 evoliuion of native forms, hybridization must be assigned a very 

 important role. It is believed tluit no more valual)le aid to re- 

 searcli at the present time could be made than by a well c(msid- 

 eretl digest and descriptive list of forms of natural hybrids. 



D. T. MacDougal. 



A RECEXT WORK OX EVOLUTIOX. 



WiUiaDi Lawrencp Toii'pr in his recently published investi- 

 gation of evolution in Chrysomelid beetles of the genus Lcpflno- 

 farsd (Carnegie Institutitm of Washington, Publication Xo. 48) 

 ])resents much that l)otanists as well as zoologists will read with 

 interest and profit. 



It is shown that the main ecological factors which control 

 the distribution of all the groups of the genus are, first, moisture ; 

 second, temjjerature ; third, soil; and fourth, altitude; but in 

 addition to these are considered effects of habits in <lispersal, 

 winds, and available food. Xeedless to say, the viewpoint of the 

 writer is the dynamic. Of the static he says: "The study of 

 aniiiud distribution from this standpoint is a dead and profitless 

 ])iirsuit." 



Accordingly the task of the ]u-esent time is to explain the 

 facts of distribution as we now find them in terms of the relation 

 of organisms to each other and to their environmental complexes. 

 It is found that the grou])s of species of this genus and the species 

 themselves are confined to particular liabitats, which habitats an* 



