204 FERTILISATION OF THE GOODENIACE^, 



upwards in the middle, and bursts the bud open on the upper side 

 (Fig. 9), and at the same time the pollen begins to be forced 

 through the slit at the mouth of the indusium by the growth of 

 the stigma. I have noticed in some flowers that the mouth opens 

 quickly and allows the pollen to drop out in a solid mass. Tlie 

 petals now expand, and by a further bending of the style, the 

 mouth of the cup rests upon and in contact with the brush-tipped 

 hairs on the petals. During this period, the leaf from the axil of 

 which the flower springs, reaches the horizontal position, and when 

 the flower is fully open it is spread out on the leaf which forms a 

 platform on which insects visiting the flower can alight. I have 

 not observed this correlation of movements and growth between 

 the leaf and flower in any other member of the oider. When the 

 flower is fully open, the stigma continues to grow outward from 

 the bottom of the indusium, and forces a constant shower of pollen 

 between the hairs at the mouth, which falls on the brush-like hairs 

 on the petals. Any insect visiting the flower is guided in the 

 right direction by the lateral petals, the convergence of the central 

 petals, and the guiding lines of colour ; to reach the throat of tlie 

 flower it has to force itself under the pollen-shedding cup, and in 

 doing this it is dusted with pollen on the dorsal surface by the 

 cup, and on the ventral surface by the brushes on the petals. 



Before the stigma has grown so much as to project from the 

 opening of the indusium, the flower withers, the lateral petals a 

 considerable time before the central ones, and the supporting leaf, 

 by a twisting of the leaf-stalk, moves round so as to be above the 

 flower, and then turns on one side and conceals it. It is during 

 this movement, and after it is complete, that the stigma first 

 emerges from the indusium (Fig. 9). It is difiicult to give any 

 reason for this concealment, as it is just at the stage when insects 

 would begin to be useful to the plant by placing pollen from other 

 flowers on the stigma, that concealment begins. The withering, 

 too, seems to indicate that the plant no longer requires the aid of 

 insects. But there is evidence that insects do visit these withered 

 and concealed flowers, for if a series of stigmata from them be 

 examined, most of them will be found to have moth scales adhering 



