460 Small. — Pollen-presentation Mechanism in the Compositae. 
part of the flower in which the tendency to economy has not previously 
been recognized. 
Considering the appendages of the styles and stamens in the light of 
the idea that economy of pollen is a factor in the success of the Compositae, 
the value of the hairs on the exterior of the style branches and the 
appendages of the style branches becomes apparent at once. Cassini 
recognized the value of these hairs in sweeping out all the pollen from the 
dehisced sacs, but a new emphasis is given to their efficiency, and an 
explanation is afforded of the development of rings of long hairs at or 
below the point of branching, as in types X and XI, Fig. 2, the spreading 
hairs at the apex of the style branches in types IV and V, and at the base 
of the appendages in types VII and VIII. The functions of the staminal 
appendages, hitherto obscure, become more obvious, for with the 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 membranous prolongation at the apex of each anther. 
This is a very simple method of reducing the polliniferous tissue while 
preserving the efficiency of the staminal tube in the pollen-presentation 
mechanism. The function of the basal appendages is also made clear, since 
a tube terminating in ten more or less hemispherical lobes, as in type 3, 
Fig. 1, 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 were 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 so far as the 
pollen-presentation mechanism was concerned. 
The question immediately arises whether these conditions actually 
occur at the time of the dehiscence of the anthers. A considerable number 
of species has been examined, and nothing has been found which is incom¬ 
patible with the above explanation of the functions of the appendages. 
Each case, however, must be considered separately because a conical style 
appendage of type VIII may be quite efficient in the absence of basal 
appendages to the stamens, and the figures in the tables bear this out in 
a very striking way for the Astereae, Heliantheae, and Helenieae. Much 
exact work remains to be done on this point, and it is purposed to make 
this and other problems subjects for further instalments of these studies. 
The hypothesis that the appendages of the style branches and the 
