The Wanderings of the Groim(heJ. 80 



different from those of the original home and of the paths of 

 migration of the groundsel that, within the next geological period 

 (Oligocenc) still another set of changes took eflPect on the colonist 

 giving rise to the elecampane and golden samphire type. Tliis 

 offshoot arose by an increase in the number of ray florets on 

 account of the rich soil and favourable conditions for luxuriant 

 grovi^th ; but very soon, geologically speaking, this same ty])e 

 developed into thistles by reason of the considerable drying up of 

 the eastern end of the Great Central Sea and the resulting hot 

 dry climate. 



Meanwhile the descendants of the groundsel in its original 

 home, multiplying, spreading and undergoing various slight 

 changes in response to new and more favourable conditions, gave 

 rise to other new types such as Trixis and Gerbera in Brazil. 

 In the succeeding geological period (Miocene) the same Amazonian 

 region was the scene of the origin of several still newer types, 

 such as Liabum, Vernonia and hemp agrimony {Eupatorium). 

 About the same time in Mexico the Michaelmas daisy type gave 

 rise to the true daisy (Bellis) and some of the Mexican groundsels 

 developed into the French marigold type (Tagetes), mainly as the 

 result of the first stages in the drying-up of the western end of 

 the Great Central Sea. 



Before the Pliocene period was well begun an extensive 

 migration took place southwards along the mountains of eastern 

 Africa ; not only the groundsels but the golden samphire and 

 edelweiss types took part in this movement. South Africa was 

 at this date beginning to become largely a semi-desert region, 

 and such conditions had their inevitable effects on the last type, 

 which originally came from near the zones of eternal snow on the 

 Andes. In South Africa it gave rise to the " everlasting " type 

 {Hellchrysum) . A little later on in the wooded regions which 

 still occurred along the rivers, some of the groundsels lost their 

 pappus and developed other means of dispersal, just as had 

 happened before under such conditions in Brazil, Mexico and the 

 Mediterranean. In South Africa this change was in some cases 



