966 



P. S. — After a renewed and most gratifying examination of Cam- 

 panula rotundifolia this morning, I can now testify that the stigma is 

 the true channel by which fertilization is effected, I have traced the 

 pollen-tubes in abundance from the stigma downwards, in unbroken 

 continuity, to the distance of half an inch ; and the evidence of their 

 being prolonged until they penetrate the ovule is so exceedingly 

 strong that 1 now fully admit and believe the fact. The course of 

 the tubes from the base of the style is by a sudden turn from the up- 

 per part of the point of junction with the placenta, passing outwards 

 between two contiguous surfaces in the centre of the mass to the up- 

 per part, and thence over the whole surface of the placenta, to which 

 the foramen of each ovule is closely applied ; hence it is not difficult 

 to delach an ovule with a tube of six times its own length still adher- 

 ing to the foramen. This T have repeatedly done. Sometimes a 

 tube appears to pass close to the foramen without entering it, or 

 otherwise two tubes enter the foramen. I cannot account for my not 

 having seen this before, except through my not having dissected the 

 ovarium in a sufliciently advanced state. The tardy admission of 

 one who has been so long sceptical will perhaps be thought conclu- 

 sive ; but any microscopist may verify my observations with a lens 

 of moderate power. The stigma obtains its pollen by its branches 

 becoming revolute, when its surface comes into direct contact with 

 the pollen-grains, already profusely scattered upon the upper part of 

 the style. Thus an ingenious theory fails of one of its main supports, 

 if it be not altogether refuted. 



W, Wilson. 



Orford Mount, September 8, 1847. 



Remarks on Polygala depressa of Wenderoth. 

 By W. A. Bromfield, M.D., F.L.S. 



Polygala depressa. — A plant exactly answering to the description 

 given of P. depressa of Wenderoth, the P. serpyllacea of Weihe, I 

 found in May, 1846, growing sparingly in bare, gravelly spots on 

 Bleak Down, an elevated tract of barren heath on the road from 

 Newport to Niton, in this island, and which, so far as I am aware, 

 has not been noticed in England even as a variety of the common 

 milkwort {P. vulgaris, L.), in which light I was then, and still am 

 disposed to regard it. Absence abroad up to a period much too late 



