1 66 Plants and their Ways in South Africa 



There in the daytime it rests, hidden in the half-closed flowers, 

 matching them so nearly in colour with the front wings 

 that it is difficult to detect. Like other night flowers, they are 

 white, so that they can be seen from a distance. At night 

 the flowers expand like large six-pointed stars, and the 

 mother moth begins her rounds. First she goes from 

 one stamen to another, until she has obtained a ball of 

 pollen nearly as large as her head, which is held by her 

 front legs against her body. She is not intent on nectar, 

 nor does she gather pollen as bees do for making bee- 

 bread. Why, then, does she carry her precious load? She 

 now lays her eggs in a pistil. They pass from her body through 

 a long tube furnished with a saw. With this she pierces the 

 ovary and deftly places an egg just beside a tiny ovule. When 

 the eggs hatch out, the little larvae have the growing seeds for 

 food. Now we know that the ovules will not develop into 

 seeds unless they receive the power from the pollen. It looks 

 as though the moth knew this long before we did, for when she 

 lays an egg up she runs with her ball of pollen, thrusts it into 

 the cleft stigma, and works her head up and down vigorously 

 to ensure that some pollen has been driven home; then she 

 runs back, lays another egg, and repeats the operation. 



One year a Yucca in a neighbouring garden surprised us by 

 bearing fruit. The fruits did not show the spots which result 

 from the injury when the eggs are placed, and no larvae were 

 found among the seeds. Had our own large grey moths per- 

 formed the service ? This year a few bees were seen among 

 the other Yucca flowers, but hopes for iruit were in vain, for 

 the bare withered stalks a few weeks later told that once more 

 the flowers exiled from home had wasted their sweetness. 1 



The scarlet bells oiAntholyza revoluta, Burm., are often found 

 in fields of corn. Their long curved tubes are narrowed at the 

 base and suddenly enlarge about the middle, where honey is 

 made which fills the lower part of the tube. The stamen at- 

 tached to the front sepal is arched backward and brought into 

 line with the two at the back, which by a twist of the filaments 

 turn the anthers so that they all discharge their pollen toward 

 the centre of the flower. In the younger flowers at the top of 



1 In some parts of South Africa the Yucca sets seeds regularly. 



