132 Plants and their Ways in South Africa 



day, but give forth their fragrance, as do so many of our flowers, 

 only to attract night visitors. Have you ever seen the seeds 

 after flowering ? For seven years the flowers of one plant have 

 been watched, and seven times they have withered and fallen 

 off, for Nature retains no useless burdens. The moth which 

 can aid in quickening the seeds has been left behind in Mexico. 

 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 larv^ 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 

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

 the other Yucca flowers, but hopes for fruit 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. 



The scarlet bells of Antholyza revoluta are often found in 

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



