AX EXDOMVCES FROM APPLE. 59 



prune decoction and fixed in picro-formol and in absolute al- 

 cohol. 



The conidia of this fungus are uninucleate. \\'hen a conidium 

 germinates, it becomes very much swollen and usually puts out 

 a single germ tube. The nucleus moves over to the side of the 

 conidium from which the germ tube grows but does not move 

 out much into the germ tube. \Vhen the germ tube has grown 

 out to some length the nucleus divides and one of the 

 daughter nuclei moves out into the germ tube which then di- 

 vides by a cross wall giving two cells each of which contains a 

 single nucleus. By further growth and division, a branched 

 mycelium consisting of many cells is formed. Each cell :s un- 

 inucleate. This dififers from what Miss Stoppel (15) found in 

 Ercniasciis fcrfilis in which the number of nuclei in the cells 

 varies from one to 15, and in which 6 to 8 nuclei are found in 

 the germ tube. 



The ascus develops from a single branch from the mycelium 

 and not from a fusion of two branches as is the case in Ercnias- 

 ciis. One or more asci may develop from a single cell. Fig. 65. 

 There is no fusion of nuclei in the ascus and none has been 

 observed in the mycelium preceding the formation of the a-cus. 

 The nucleus does not move out into the developing ascus until 

 the outer end of the branch has rounded out and has attained 

 some size. The writer has observed a consideralile numlier of 

 cases in which a single nucleus had moved only part way into 

 the ascus when the material was fixed. A number of cases 

 have been observed in which it appeared that the nucleus di- 

 vides at the opening of the branch from th.e cell of the myceliimi, 

 one nucleus going into the young developing ascus and the other 

 remaining in the cell. It would reem that such a division would 

 be necessary in the case of cells which produce more than one 

 ascus. Two cases in which division is taking place at this point 

 are shown in Fig. 70. It has not been possible to determine 

 whether the nuclear divisions are mitotic or amitotic. In «ome 

 cases, there is somewhat the appearance that would be given 

 l)y the tlircads of a low form of spindle connecting the chro- 

 matin which is to form the two nuclei or the same appearance 

 might be given hv the separating of two nuclei formed by direct 

 division. The nuclei are small but tlie greatest difficulty is that 

 no method of fixation which I have tried brings out the nuclear 

 ficures with sufficient clearness to enable one to determine with 



