40 OX PLANTS AND INSECTS. [LECT. 



five stamens in front of the sepals grow very rapidly for 

 about two hours, so that they emerge from the flower ; 

 the pollen ripens, and is exposed by the bursting of the 

 anther. So the flower remains through the night, very 

 attractive to, and much visited by, moths. Towards three 

 in the morning the scent ceases, the anthers begin to 

 shrivel up or drop off, the filaments turn themselves out- 

 wards, so as to be out of the way, while the petals, on the 

 contrary, begin to roll themselves up, so that by daylight 

 they close the aperture of the flower, and present only 

 their brownish -green undersides to view ; which, more- 

 over, are thrown into numerous wrinkles. Thus, by the 

 morning's light, the flower has all the appearance of 

 being faded. It has no smell, and the honey is covered 

 over by the petals. So it remains all day. Towards 

 evening, however, everything is changed. The petals 

 unfold themselves ; by eight o'clock the flower is as 

 fragrant as before, the second set of stamens have 

 rapidly grown, their anthers are open, and the pollen 

 again exposed. By morning the flower is again " asleep," 

 the anthers are shrivelled, the scent has ceased, and the 

 petals rolled up as before. The third evening, again the 

 same process occurs, but this time it is the pistil which 

 grows : the long spiral stigmas on the third evening take 

 the position which on the previous two had been occupied 

 by the anthers, and can hardly fail to be dusted by 

 moths with pollen brought from another flower. 



An objection to the view that the sleep of flowers is 

 regulated by the visits of insects, might be derived from 

 the cases of those flowers which close early in the day, 

 the well-known Tragopogon pratense, or " John Gro-to- 

 bed at Noon/' for instance ; still more, such species as 



