48 MR. J. P. M. WEALE ON THE FERTILIZATION OF 
abundance on the open grassy flats, almost every flower that I 
have examined has been fertilized, 
In another species of Habenaria found on the Kagaberg, in 
February 1869, and on my farm * Brooklyn” in February and 
March 1869, the whole caudicle, when ¿n situ, is relatively much 
shorter than in any of the preceding species, and does not con- 
tract on withdrawal, but is nearly rigid. The viscid disk is seen 
to be oval on its outside, with a slight extension laterally. 
The caudicle at its juncture with the disk is somewhat trian- 
gular, the outer angle joining the projecting portion of the disk. 
This triangular appearance is produced by its being folded over 
on itself, something like a T-hinge ; at the same time, as if this fold 
had not produced a sufficient shortening of the caudicle, a thin 
tail-like portion projects beyond. 
I was, at the time when I first examined it, inclined to think 
that the thickened fold was the homologue of the drum-like pedicel 
of H. chlorantha mentioned by Mr. Darwin; but the structure 
under the microscope appeared to indicate that it is really a 
thickened portion of the caudicle corresponding to the discal ex- 
tremities of the caudicle in the two former species. 
I watched very carefully to see whether any movement took 
place on removal, and was at first inclined to think so: but 
-on more careful examination I found that I was mistaken; in 
fact the incurved portion of the pollen-masses is quite sufficient 
to place them in a proper position for the fertilization of the 
flower. I found considerable difficulty in removing the viscid 
disk, although its prominent position seemed to offer as great fa- 
cilities as in the other species; and the constant fertilization of 
the flowers throughout a whole spike leads me to suspect that my 
pin had too smooth a surface for the viscid disk to adhere to. 
Observations on the Mode in which certain Species of Asclepiadew 
are fertilized. Abstract of a paper by J. P. Mansen WEALE, 
B.A. Oxon. (Communicated by CuHartzs Darwin, Esq. 
F.R. & L.SS.) 
[Read November 3, 1870.] 
Ox placing the blossoms of Gomphocarpus physocarpus in water, 1 
noticed that numbers of flies, attracted by the sweet nectar con- 
