228 
James Small. 
the eastern end of the Mediterranean, of which the dwarfed, re¬ 
duced, spinescent Gymnarrhena was a natural inhabitant. The 
progressive elaboration of the style branches included the formation 
of the ring of hairs characteristic of the Cynarese and the 
orthogenetic economy in polliniferous tissue led to the further 
elaboration of the anther tails. By an elongation of the achene 
and a reduction in the length of the receptacular setae the pappus 
was again freed and Centaurea was produced. Being economical 
and easily dispersed by wind this type multiplied and spread to 
occupy the new habitat. 
About the same time (end of the Oligocene and beginning of 
the Miocene) another of the periodical invasions of the Amazon¬ 
ian headwaters took place. Two mountain tribes took part in this 
invasion and the new environment of moist woods and caatingas 
had the same effect in both cases. The pappus was again rendered 
of little use and as a consequence became more or less atrophied 
by fusion. This change was most pronounced in the Spilaiithes 
coterie and the Calea (Galinsoginae) type was the result. The 
numerous progeny of the Andine Senecios were not so susceptible, 
and the fusion of pappus hairs was more or less confined to the 
outer rows ; the style branches in this case, however, underwent 
considerable elongation and Liabum was the result. This genus 
afterwards re-ascended the Andes, undergoing the usual changes, 
becoming dwarfed and unicapitulate. 
A neighbouring region, the Chilian part of the Andes, was 
invaded more or less simultaneously by Mutisia and its fellow genera 
from the foot-hills. This regaining of a region where the conditions 
rendered the food-supply of the capitulum rather problematical led 
to the complete suppression of the large corollas of the ray florets. 
At the same time the plumose pappus was once again in a position 
to exercise its natural efficiency and reduction in the number of 
fruits was possible. This was affected by the sterilisation of some 
or all of the florets of the capitulum and Chuquiragua came into 
existence. 
Just as its cousin, or rather niece, Chaptalia raced along the 
mountain ranges on regaining an efficient pappus in a suitable 
environment, so did Chuquiragua. Like Chaptalia also, this new 
genus was transformed on crossing the Alaska-Siberian bridge by 
an increase in the corolla material, which was rendered possible by 
the mesophytic conditions of the upland plains of China. Ainslicea 
is the name now giving to the transformed Chuquiragua. This 
