Origin and Development of the Composite 213 
corolla tube of a given length and the stamens in proportion, the 
amount of pollen produced can be reduced and the staminal tube 
remain the same length by the production of a membranaceous pro¬ 
longation at the apex of each anther. This is a very simple method 
of reducing the polliniferous tissue while preserving efficiency of the 
staminal tube in the pollen-presentation mechanism. The function 
of the basal appendages is also made clear, since a tube term¬ 
inating in ten more or less hemispherical lobes, as in type 3, could 
not be closed entirely by the style unless that organ actually 
entered the tube for some distance, in which case the pollen in 
that part of the sac past which the style had grown would be more 
or less lost for pollination purposes, unless it was swept up the 
tube by hairs situated lower down on the style. If the apex of the 
style merely reached to the lobes when the anthers dehisced, some 
of the pollen would fall through the interstices to the bottom of 
the corolla tube and thus be lost. If, however, the hemispherical 
lobes were prolonged into flattened auricles or ciliate tails or more 
elaborate appendages, the style, with or without appendages, could 
close the lower end of the staminal tube completely without 
encroaching on the polliniferous region, and thus no pollen would 
be wasted as far as the pollen-presentation mechanism was 
concerned.” 
Prom the further extended study of many forms there is no 
doubt that the above is the correct explanation of the variations in 
structure of the styles and stamens, and it is considered proved 
that these appendages and variations are the several modes of 
expression of a tendency in the Compositas to economy of pollen, 
which is limited only by the biological necessity of providing 
sufficient pollen to ensure fertilisation. 
Except in the relatively primitive groups, the Anthemideas and 
Senecioneae, relatively inefficient anther tubes are combined with 
efficient styles, as in the Eupatorieae, Astereae, Heliantheae and 
Helenieae, or relatively inefficient styles are combined with efficient 
anther tubes, as in the Vernonieae, Inuleae, Calenduleae, Arctotideae 
and Cichorieae, or both styles and anther tubes are efficient, as in 
the Mutisieae and Cynareae. 
Another point which is brought out by further study of the 
structure of the stamen is that Cassini’s interpretation of the 
apical appendage and the “ article anthdrifere ” as continuations of 
the connective is supported by the fact that the structure of these 
three parts of the stamen is very similar. This leads to the con- 
