164 



DICOTYLEDONS 



(fig. 129, right-hand): this collection is an infructescence (not a 

 compound fruit), because it is formed by a number of flowers 

 (not by one flower only). Dissemination. — The fruits are dis- 



' 207 persed by the wind, 

 and the pappus 

 forms a parachute. 

 Pollination. — The 

 flowers are prote- 

 randrous. The 

 anthers dehisce 

 ig '■ . around the style be- 



fore the latter has 

 m' \, attained its full 

 length, and whilst 

 the two terminal 

 arms of the style 

 are still applied to 

 each other (fig. 204). 

 The style then elon- 

 gates and the hairs 

 on its sides brush 

 the pollen out of the tube formed by the ring of anthers 

 (fig. 205). Inasmuch as these hairs serve to hold and 

 carry up the pollen, they are termed "collecting-hairs." 

 The style thus acts like a brush employed in sweeping a 

 chimney. Insects now visiting the flower to sip at the nectar 

 touch the pollen thus carried up on the style. Soon the arms 

 of the style separate and the stigmas on their upper faces are 

 ready for the reception of pollen (fig. 206). An insect dusted 

 with pollen, and visiting flowers at this later stage, will 

 transfer pollen on to the stigma, and thus may effect cross- 

 pollination. But if the stigmas are not pollinated, the branches 

 of the style continue to curl downwards, and even execute 

 complete curves at their ends, so that eventually they touch 

 the collecting hairs (fig. 207), and are self-pollinated. 



Types II., III., IV. : DAISY (Beuis perennis) : SUN- 

 FLOWER {Helianthus annuus) : OX-EYE DAISY 

 \Chrysanthemum leucanthemum). 

 These three plants also have capitula of flowers (fig. 208), 

 which differ from the Dandelion-heads in that they possess 



Figs. 204-207. — Diagrammatic figures of the behaviour 

 of the antherSj style, and stigmas of Dandelion. 



