190 THE STRUCTURE OF FLOWERS. 



this will remind the reader that, since floral whorls are based 

 upon pbyllotaxis, ten stamens could not possibly form a 

 cycle ; and aUhough the eight stamens of a Heath might do 

 so, there is nothing in the leaf arrangement of that genus to 

 suggest their being a whorl of the f type. 



Since the petaline cords are usually united to the 

 staminal ones, the fact that the petaline stamens get 

 sometimes, as it were, " dragged outwards," offers really 

 no great difficulty ; but is, so to say, a mere accident brought 

 aboat by the adaptations of the flower to insect agency. 



Indeed, to interpret these irregularities in the emer- 

 gence, one must look to the final condition to see if there 

 are any ultimate results in correlation with them. In Oxalis 

 we get heterostylism with its corresponding different lengths 

 of the filaments, and the necessary adjustments of the latter; 

 since there are at least two sets in each flower, for insects to 

 readily secure the pollen. In Heaths all the anthers are 

 arranged in a ring round the style, pressing their cells 

 against it, and so closely approximated, that when a bee 

 dislocates one by pushing the lever-like auricle to one side, 

 she dislocates the whole, and so receives a shower of pollen. 



These final arrangements, therefore, are suggestive of the 

 reason why the points of emergence of the stamens occur just 

 where they do. 



In the case of Hypericum, where the stamens emerge 

 centrifugally, from a definite number of original papillae, 

 three or five as the case may be, the stigmas extend 

 ontwards ; so that, if they have not been pollinated by 

 insects, they can come in contact with the latest formed or 

 the outermost anthers. 



