394 BOTANICAL GAZETTE [NOVEMBER 
Cytology of Ascomycetes.—Miss FRASER and Miss WELSFORD have recently 
added another contribution's to their important series on the cytology of the 
Ascomycetes. The present investigation deals with two additional Discomy- 
cetes—Otidea aurantia and Peziza vesiculosa, The authors have studied princi- 
pally the triple reducing divisions in the ascus, and their observations accord in 
the main with those of HARPER on Phyllactinia. They find in these two species, 
however, intermediate conditions between the early pairing of the chromosomes 
in Phyllactinia and their complete independence during the stages preceding 
reduction in Humaria, as described in an earlier paper by Dr. FRASER. 
Otidea, for example, the chromosomes do not pair till the prophases of the third 
(or brachymeiotic) division; whereas in Peziza vesiculosa they unite during the 
prophases of the second division in the ascus. This variation in the time of 
chromosome union, as described for these species, is compared in tabular form 
with the conditions which obtain in Humaria, Galactinia, and Phyllactinia. ae 
The authors describe two phases of the reduction processes—the meiotic 
phase, embracing the first and second divisions in the ascus, distinguished in 
Otidea by four chromosomes and in Peziza vesiculosa by eight chromosomes; and 
brachymeiosis, involving the second reduction, when the two sets of post-melotic 
chromosomes become separated during the third division, thus resulting in tue 
chromosomes in Otidea, and four in Peziza. A definite synaptic contraction 
occurs in connection with meiosis, similar to that first described by HARPF® m 
Phyllactinia; but, unlike the case in Phyllactinia and in Humaria, a second con- 
traction takes place in the two forms studied at the beginning of brachymetosis- 
The authors regard the presence of both meiosis and brachymeiosis as evidence 
of the occurrence of two fusions in the life-history of these forms; although 10 
— — cell, and the other with the somatic division as it occu’ 
archesporial cells and in the ovary wall. : 
The results may;be summarized as follows: (1) The nuclear ret! 
ns to the cytology 
culum in 
of re canoes H.C. I. AND WELsForD, E. J., Further contributio 
e Ascomycetes. Annals of Botany 22:465-477. pls. 26, 27- 190°: ae 
*4SYKEs, M. G., Nuclear division in Funkia. Archiv fir Zellforschung 1:3 
398. pls. 8, 9. fig. 1. 1908 
25-527" 
pl. 16. 1908. NoteJon the,number of the somatic chromosomes. Idem ¥+5 
