490 



Transactions of the Society. 



In the following table I put species of the same family opposite 

 one another. 



The measurements can only be taken as approximate, for 

 different grains of the pollen of the same flower sometimes differ 

 somewhat in size. Moreover, the actual size of the pollen will 

 depend not merely on the length but on the shape. A spherical 

 pollen will, of course, contain more than an elliptic grain of 

 the same length. The pollen of Convolvulus arvensis is as long as 

 that of C. sepium, but the latter is much broader. 



The pollen-grains of Antirrhinum majus are almost exactly 

 of the same length as those of Linaria vulgaris, although the pistil 

 is much longer ; but, on the other hand, they are much broader, so 

 that the cubical contents are larger. 



Still, though only approximate, the figures in the following 

 table are very significant. For most of them I am indebted to my 

 excellent assistant, Mr. Eraser. 



Name of Plant 



ErantJiis hyemalis . . 

 Pxonia veitchii 

 Delphiniu')n formosuin 

 Aconitmn napcUus . . 



Berberis vulgaris 



NympJixa alba 

 Ntiphar luteum 



Hesperis matronalis 

 Brassica oleracea . . 

 Gheiranthus cheiri 

 Brassica tenuifolia 

 B. rapa 



