Further Contributions to the Cytology of the 
Ascomycetes. 
BY 
H. C. I. FRASER, D.Sc., F.L.S., 
Lecturer in Botany , University College , Nottingham , 
AND 
E. J. WELSFORD, F.L.S., 
Botanical Assistant, Royal Holloway College , University of London. 
With Plates XXVI and XXVII, and a Figure in the Text. 
R ECENT investigations by one of us ( 13 ) have shown that in Humaria 
rutilans a meiotic reduction, involving transverse fission of the 
heterotype chromosomes, takes place in the first two divisions in the ascus, 
and further, that it is followed, in the third mitosis, by a second, or brachy- 
meiotic reduction of a simpler type. 
These processes accord with the observations of Harper ( 19 ) on 
Phyllactinia but have not been described in other forms ; the present 
researches were undertaken as a first step towards ascertaining whether 
they are of general occurrence among Ascomycetes. We have found, 
in the two species with which this paper deals, intermediate stages between 
the early union of the chromosomes in P hyllactinia and their independence 
during the stages which precede reduction in Humaria rutilans and in 
higher plants and animals. 
Material was obtained in Windsor Park during the autumns of 1906 
and 1907, and was fixed in the field in various strengths of Flemming’s 
fluid. Before staining, many of the slides were immersed for three or four 
hours in a solution of pepsin 1 and o-a per cent, hydrochloric acid at a tem- 
perature of 38° C. This treatment facilitated the study of the chromatin. 
Sections were cut 5-10 /x in thickness and were stained with Heidenhain’s 
iron-haematoxylin or with Flemming’s triple stain. 
OTIDEA AURANTIA. 
This species has a large, orange apothecium which increases con- 
siderably in size after the asci have begun to form. In the early stages 
of development a large cell with scanty contents is present, and represents, 
[Annals of Botany, Vol. XXII. No. LXXXVII. July, 1908.] 
1 See Farmer and Digby ( 10 ), p. 165. 
