FIRE-WEEDS. 469 



essential to the beginning of the process of germination. It is 

 said that in soil which has been completely sterilized, that is, 

 freed from microbes or their germs, seeds provided with all other 

 requisites for germination will fail to sprout. These experiments 

 by Duclaux 1 have not been repeated by other observers. 



1225. The appearance of abundant crops of certain plants 

 upon ground recently cleared by fire is one of the most note- 

 worthy phenomena in connection with germination. At the 

 North, two plants have obtained, par excellence, the name of 

 11 fire-weeds ;" namely, Erechtites hieracifolia, and the more 

 common willow-herb, or Epilobium angustifolium. They are 

 later replaced by shrubs, and later still by soft- wooded trees, 

 which are characteristic of burnt districts. The following sug- 

 gestions have been made in regard to their appearance : (1) that 

 the seeds have been long buried in the soil, under conditions 

 which have preserved their vitality, but which did not permit 

 them to germinate ; (2) that the seeds find their way to the 

 ground of a clearing which affords, in the ash released from 

 wood by burning, a soil most fit for germination. But no exact 

 observations have yet been made upon the subject. 



1 Comptes Rendus, c., 1885, p. 67. 



