Origin and Development of the Composite. 89 
Figs. 3-5), and is continued in the latter sub-tribe, giving 3-5 aristae 
in Adenostemma and type N in Piqueria. Type E which is common 
in the Ageratinae also occurs here in three genera and types G and 
K in other genera. Type A is again dominant in the Adenostylinae 
with types D and E as common variations. All three types occur 
in Brickellia , the chief genus, and type G occurs also but only in 
Carphochcete. 
Heliatithece. The aristate type O and its derivatives (see Fig. 
18) form the dominant types in this tribe. The tendency to lateral 
fusion and reduction giving the paleaceous and fimbriato-coroniform 
types are also present, but to a smaller extent. 
The Verhesininas is taken as the primitive sub-tribe and 
frequently shows only two aristae ; that this is a reduced not a 
primitive pappus-form will be clear from the above account of the 
pappus (Sect. B) and this view is supported by the fact that the 
other reduced form, type N, is also of frequent occurrence in this 
same sub-tribe, and also by the fact that the pappus is frequently 
absent altogether. The setose origin is further demonstrated by 
the frequent presence of paleae of types K and L (which are clearly 
fused setae) between or among the aristae, and by the Heliantlms 
type, which is type N, with two of the major lacerations larger than 
the others, thus passing locally into type K. 
The pappus is absent from the Ambrosiinae, except in one genus, 
Dicoria, which shows a feebly developed type N structure. In the 
Petrobiinae the pappus is absent or of type N in combination with 
2-4 structures of type G. This same combined type, where a few 
of the fimbriations of type N become thickened and elongated, thus 
passing locally into type G, occurs in the Lagasceinae. 
The Zinniinae usually have the pappus absent, but type O is 
present occasionally. The Coreopsidinae are characterised by type 
O frequently developing into types Pa and Pb or being reduced 
to types R or Qa. The pappus is also sometimes absent, so that 
the tendency to reduction reaches its extreme expression. 
This tendency to reduction is developed further in the Melam- 
podiinae, the pappus here being frequently absent, and showing only 
types R, Qa and N when present, except in a few cases where types 
O and G occur. 
The tendency to reduction is even more accentuated in the* 
Milleriinae (cp. Fig. 7), where in most genera the pappus is entirely 
absent, showing type N in only two genera and four aristas of type 
O in another genus. 
The affinity between the Galinsoginae and Madiinse which is 
