BY E. HAVILAND. 423 



that the fovilla might be discharged by the pollen grains directly 

 upon the foramen of the ovule, as occurs in a genus of not very 

 dissimilar construction, in the G-ymospermous order Gnetacese, 

 but subsequent examination proved that this could not be so. 

 Measuring, in four or five flowers, the diameter of the tube of the 

 style by the micrometer eye piece, I found it to be 1( *, of an inch, 

 while the pollen grains were less than ^^ So that the tube is 

 more than four times the diameter of the grains of pollen which 

 have to pass through it. In some flowers, however, I found the 

 wall of the tube thick and the passage very much smaller. The 

 placenta is not, as in many flowers, a mere point of attachment of 

 the ovules to the ovary, but is large, fleshy, and globular, nearly 

 filling the ovary. It is quite free, except its connection at the 

 base ; and the ovules are embedded in it. It is owing to this, that 

 the ovules cannot be fertilised by the direct action of the pollen 

 grains, as I at first thought possible, but require the intervention 

 of pollen tubes. The substance of the placenta, however, is very 

 spongy and open, so that the pollen tubes can easily penetrate it. 

 In a section of the nearly mature fruit, I have rarely found more 

 than one seed perfect, but small depressions can be seen in the 

 mass of the placenta filled with the debris of the ovules that have 

 not been fertilised. I have been asked once or twice, by young 

 botanists, how it occurs, that plants having many ovules, frequently 

 produce but two or three seeds. I think a transverse section of 

 the fruit of this plant under a low miscroscopic power, would be 

 the best answer that could be given to such an enquiry. 



The proportion of perfect and imperfect flowers upon any plant 

 of this species of Myrsine I should think nearly equal. In the 

 first supply I received from Mr. Deane, I found all perfect, the 

 ovaries containing ovules, the anthers full of pollen, except in cases 

 where they had matured and opened ; and in most the style a 

 short open tube. I am inclined to think, that the opening of the 

 style increases as the pollen ripens ; so that when it is fully ripe, 

 the style is fully open to receive it ; but I merely suggest this, I 

 am not at all sure of it. In the second supply of flowers, from the 

 same tree, I found every one imperfect. Ovaries without ovules, 



