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James Small. 
Carlininae. A slight degree of diphylesis is thus indicated for the 
Carlininae and this is supported by other details, which suggest the 
Atractylis-Ccirlina plexus and Xeranthewum as the two basal groups 
(cp. Lavialle above, Chap. XII, D). 
Considering the date of the origin of the Cynareae, the facts 
are that this tribe is not represented with any certainty previous to 
the upper Miocene and that the Arctium type (Carduinae) had then 
developed. If the above views on the phylesis of the tribe are 
correct this involves the previous existence of the Carduus type, 
which is also represented at the same horizon, and of the Centaurea 
type, which is not as yet reported fossil below the upper Pliocene. 
The time interval necessary for this development takes the origin 
of the Cynareae back to the lower Miocene or Upper Oligocene. 
As the shrinking of the Central Sea reached its maximum about 
this time, the semi-desert condition of the eastern Mediterranean 
region would appear to have developed then. The connection 
between the origin of the Cynareae and the ecological conditions in 
the place of origin has been discussed previously, and the 
synchronising of events in climatic evolution with events in plant 
evolution appears to be exemplified in the origin of the Cynareae as 
well as in the origin of Senecio. 
Mutisiece. The basal group of the Mutisiese is undoubtedly 
the Nassauviinae and the basal genus is shown to be Trixis by 
the characters of the styles, stamens, pappus and other achenial 
hairs, receptacle and involucre. This is confirmed by the geo¬ 
graphical distribution of the genus and sub-tribe and by the 
Senecionoid habit of many species of Trixis. The colour of the 
corolla in Trixis is also primitive and the distinguishing feature is 
the homogamous capitulum of bilabiate florets. Since the ray 
floret of Senecio and other radiate genera has been shown to be 
essentially bilabiate, and since it has also been shown, though with 
less certainty, that the number of rows of bilabiate florets, i.e., the 
the amount of “ doubling,” depends on the food supply of the 
capitulum, the change from Senecio to Trixis , from the Senecioneae 
to the Mutisieae, is evidently one which is largely dependent on 
ecological conditions. 
In Chap. V, D, it was suggested that Mutisia gave rise to the 
rest of the Onoseridinae and to the Gochnatiinae, while Onoseris, as 
the other member of the basal plexus of the Onoseridinae, gave the 
Gerberinae. The evolution of these groups is further discussed in 
Chap. X. Chuquiragua is suggested as the basal genus of the 
