354 ANNUAL KECORD OF SCIENCE AND INDUSTRY. 



the wind on the distribution of seeds in the mountain regions ; 

 and, referring to the popular impression that the winds per- 

 form a very important part in the distribution of plants, 

 quotes from Kerner and from Mr. Bentham to show that the 

 assumption rests upon insufficient data. If that portion of 

 tliistle-down which has been carried to a considerable distance 

 by a high wind be examined, it will generally be found to 

 have left its seed behind it. And it frequently happens that 

 seeds well w^inged, or provided with light pappus, are less 

 widely distributed than other forms of compositae without 

 such pappus. 



The rapid spread of the common thistle, in any new coun- 

 try, is referred to the persistent vitality of the roots quite as 

 much as to the dispersion of the seeds ; and if the individuals 

 are examined, they will generally be found to be all of one 

 sex, showing that they must have been propagated by the 

 division of the same individual. Reference is also made to 

 the Canadian water-weed, Elodea canadensis^ which filled up 

 the water-courses and canals of England within a few years 

 of its first appearance; and it is stated that to this day the 

 male plant is entirely unknown in that country, and that all 

 may have sprung, by subdivision, from the first imported spec- 

 imen. 



The memoir of Mr. Kerner is based upon a careful exami- 

 nation of plants growing on moraines, and of the seeds found 

 on the surface of glaciers ; and he finds that a large number 

 of these, constituting the moraine flora, are species widely 

 distributed over the high mountains in immediate proximity 

 to the glacier. Again, in regard to the seeds on the glaciers, 

 he finds not a single one which does not belong to a species 

 inhabiting the adjacent mountain slopes or valleys; and he 

 is therefore of the impression that the conveyance of seeds, 

 even Avhen provided wdth apparatus calculated for being 

 floated in the air by horizontal currents, takes place only 

 within very circumscribed limits ; and that the prevalent 

 opinion, that they may thus be carried for very great dis- 

 tances, is not supported by facts. 12 A^ June 27, 1872, 164. 



INFLUENCE OF CLIMATE AND MANURES UPON PLANTS. 



In the Journal of the Horticultural Society of London is 

 given a second report by M. T. Masters upon extended exper- 



