142 DEVELOPMENT OF THE OVULUM 
My own observations made on 3 or 4 genera both with 
pendulous and erect masses, lead me to agree entirely with 
the statement of Mr. Brown, and although I have seen 
protrusion without change of position, in no instance has 
such been attended with the performance of fecundation. 
Mr. Brown, however, states, that protrusion was often found ` 
to take place in Asclep. phytolaccoides without any change 
of position. “ The tubes produced in this situation often 
acquire a great length, but coming immediately on their pro- 
trusion from the mass in contact with the membrane of the 
anther , their course is necessarily altered ; and in their new 
direction which is generally upwards, they not unfrequently 
arrive at the top of the cell, or even extend beyond it." 
It is thus barely possible that in some cases they may find 
their way between the anthers, and so reach the point, 
on which they can penetrate into the style. 
The next point, regards the existence of a tissue analo- 
gous to that usually forming a stigmatic surface, at the point 
of entrance of the tubes. Mr. Brown, whose observations 
were made on 7 species of Asclepias, and on Cynanchum, 
(Vincetoxicum nigrum) distinctly states that in no instance 
could he “ observe the slightest appearance of secretion, or 
any difference whatever in texture, between that part and the 
general surface of the stigma." 
My observations lead me to infer, that in one genus such 
difference does exist, in another it certainly does not. 
M. Brongniart's observations, were made on Asclepias 
syriaca, A. amena, and A. fruticosa, as he distinctly describes 
the base of the stigma close to the summit of the style, 
as being really stigmatie, and as being continued into the in- 
terior of the style. Memoire p. 21. 
Connected with this is his obvious misunderstanding of 
the relations of the anthers one to another, as well as to the 
stigma; at least such is the construction I put upon this 
passage, “si on examine à la méme époque le stigmate et ses 
relations avec les anthéres, on voit que cet organe trés-volu- 
meneux et commun aux deux styles, d’ une forme á peu prés 
