THE COMMON ARUM 



arranged the}^ were for pollination ; but the 

 appearance of the insects, followed by the secretion 

 of the nectar, and the fact that the female flowers 

 mature before the pollen of the male flowers above 

 them is ripe, compel quite a different explanation. 



The arrangement of the floral parts, combined 

 with their orderl}'' and systematic working in con- 

 nection with the insects that visit the bloom, 

 then, are surely sufficient proof that their true 

 function has here been described. If, though, 

 further proof be needed, we have only to watch 

 the subsequent development of this singular 

 inflorescence. 



After the midges have departed with their 

 loads of pollen, no more insect visitors arrive. In 

 fact, the plant at once begins to take in the sign- 

 post. In Fig. 2'] (Plate i8) we see the arum as it 

 appeared on May 1 9th, but if we look at Fig. 3 1 

 (Plate 20), as it appeared on June 8th, we see that 

 its aspect has changed very much. Not even 

 the most giddy of midge-flies would ever attempt 

 to visit an arum as it appears in the latter illustra- 

 tion. The purple cIuId has shrivelled away and 

 turned down right to the base of the group of male 

 flowers, and likewise the hood that gave the club 

 such prominence, also now cuts a sorry figure. 

 Indeed, at first, you might think that the whole 

 thing was dead. The leaves, however, are still 

 working to build up this central structure. 



In Fig. 32 (Plate 21) we see it as it appeared on 

 August 2oth. There it will be seen that the turn 

 of the leaves to shrivel had arrived, for they had 



43 



