296 Wager . — On the Structure and 
impetus has been given to the study of the cytology and 
minute structure of the lower forms of plants, especially of 
the Fungi. Extremely interesting results have already been 
obtained, but the difficulty of prosecuting researches into the 
minute structure of parasitic Fungi is very great, mainly 
owing to the small size of these plants and their component 
parts. The work of staining sections is very difficult and 
demands much patience, owing to the great care which has 
to be taken in the application of the reagents and stains 
necessary to bring out the various details of structure, and 
still greater difficulties arise in the interpretation of the 
structures observed. To this must be due the conflicting 
statements made by various observers concerning the struc- 
ture and development of the sexual reproductive organs in 
Cyst opus and allied plants. 
I am very pleased, therefore, to be able to record here that 
Mr. Trow has independently observed many of the facts 
mentioned in this paper, and in a letter to me states that 
‘ the results so far obtained by me are, so far as I can judge 
from your descriptions, concordant with your own. In par- 
ticular, I have no doubt as to the structure of the nucleus 
(excepting possibly the presence of a nucleolus which I have 
not observed), the number of nuclei in the oogonia, the 
number found by me averaged ninety-one, and the uninucleate 
character of the oosphere.’ 
Cystopus Candidas is found in large quantities on various 
Cruciferous plants, especially on the Shepherd’s Purse, Capsella 
Bursa- pas tor is. It is difficult to find a patch of this common 
plant which does not show some of its members covered with 
the white spots and swellings so characteristic of the appear- 
ance of the Fungus, although it may easily be mistaken for 
Peronosp or a parasitica. It occurs on many other plants of the 
same order however, and Mr. Massee has been good enough 
to give me a list of the thirty-four species on which it has been 
found up to the present time. 
It has a very wide geographical distribution, being found, as 
Mr. Massee informs me, in Europe, Asia, South Africa, 
