The Pollination Mechanism of Arctotis aspera. 21 7 
Figs. 1-6. Arctotis aspera. 
Fig. 1. A semi-diagrammatic median section through a capitulum. For 
details see text. Fig. 2. Style of ray floret. Fig. 3. Style of hermaphrodite 
floret in female stage. Fig. 4. Male floret in irritable phase before being 
touched. Fig. 5. Male floret after the style has been touched as indicated by 
the arrow in Fig. 4. Fig. <!. General view of the capitulum showing curling 
of the ligulate corolla ready for the fruiting stage. 
Composition of the Capitulum. 
The centre of the disc is occupied by from five to seven rings 
of male florets, Fig. 1, A-E, tubular and sterile, with a very rudi¬ 
mentary pappus or none at all. The style acts solely as a pollen 
presenter. Outside these there is a ring of tubular hermaphrodite 
florets, PI, which vary in different capitula hut which are usually 
much the same as the F2 and F3 florets, the pappus being similar 
