16 FERTILISATION OF CLERODENDRON AND CANDOLLEA, 



proterandrous. The anthers in some flowers do not all mature at 

 once, sometimes bursting singly and sometimes in pairs, but the 

 usual course is for all to mature and burst simultaneously. The 

 tube produces nectar freely, but it can only be procured by an 

 insect with a very long proboscis, and it seemed most likely to 

 me that the sphinx or hawk moths were usually concerned in the 

 fertilisation. After the anthers have all shed their pollen, they 

 twist downwards, while the pistil straightens and thus brings the 

 stigma, now open and fit to receive pollen, into the position which 

 the stamens formerly had (fig. 2). Now this is exactly in front 

 of the neck of the tube, so that a moth feeding on the nectar is 

 certain, as it poises in front, to be smeared with pollen on the 

 lower surface of the thorax and abdomen, and this pollen is 

 transferred to the stigma when a bloom is visited which has its 

 pistil straight and the stigma mature. Inspection of the immature 

 stigmas when in the lower position showed them to be perfectly 

 free from pollen. But the mature stigmas in the upper position 

 were thickly coated with pollen, and in most cases had scales and 

 long hairs of a moth adhering to them. My conclusion, therefore, 

 was that the sphinx moths in extracting the nectar from blossoms 

 in which the stamens stood out in front of the flower, became 

 coated with the very sticky pollen ; then proceeding to flowers in 

 which the pistil was in position they deposited the pollen on the 

 stigma as they hovered over the flower, and so cross-fertilisation, 

 or to use Kerner's term, allogamy, ensued. That insects are not 

 likely to alight on the flower and so fertilise it, is evident from 

 the fact that the plane of the petals is perpendicular to the axis 

 of the tube, and that they curl round (fig. 2) towards the tube as 

 the flower matures, so that there is no platform for insects to 

 alight upon. The flowers grow in clusters, and in each cluster 

 may be found numbers in all states of maturity. The calyx, tube 

 and backs of the petals, stem and leaves are all covered with 

 hairs, both pointed and glandular, and of a soft texture. This 

 prevents ants and other crawling insects from having access to the 

 flowers, such insects only rifling the tube of its nectar without 

 fertilising the flower. 



