6 4 



RESEARCHES ON FUNGI 



grew for a while as if it would pass the peg ; the hypha and the peg 

 then made growth curvatures which resulted in their meeting and 

 fusing (C and D). Thus the compound hypha resulting from the 

 fusion came to display a very decided S-shaped twist. 



In the second fusion, two older hyphae happened to be more 

 or less parallel to one another (Fig. 39, A). One of these hyphae 

 then emitted a short branch-hypha which grew somewhat obliquely 

 toward the other older hypha (B) which, in response, sent out a 

 short opposing peg (C). The short branch-hypha and the peg 



eventually fused (D). The two 

 older hyphae were about 1 2 a 

 apart at the place where the 

 branch-hypha and the peg were 

 sent out, and the time which 

 elapsed between stage B and 

 stage D represented in Fig. 39 

 was 15 minutes. Against re- 

 garding the fusion as a peg- 

 to-peg one, we may adduce two 

 facts : (1) the oblique growth 

 of the longer fusing element, 

 and (2) the fact that the fusing 

 elements arose not simultane- 

 ously or almost so, as is usual 

 in peg-to-peg fusions, but in 

 succession at different times. I have therefore interpreted the 

 longer fusing element, not as a peg which has arisen on its parent 

 hypha as a result of this parent hypha having been stimulated by 

 the other older hypha, but as a very short branch-hypha which 

 the parent hypha would have produced even if the other older 

 hypha had not been near. 



Microsporon audouini. — An examination of photographs of the 

 mycelium of this fungus made by Davidson, Dowding, and Buller * 

 caused these authors to infer that certain short bridging hyphae, 

 connecting two parallel hyphae in a mycelium of Microsporon 



1 A. M. Davidson, E. S. Dowding, and A. H. K. Buller, " Hypha] Fusions in 

 Dermatophytes," Canadian Journal of Research, Vol. VI, 1932, p. 5. 



Fig. 39. — Sphaerobolus stellatus. Four 

 stages in a hypha-to-peg fusion 

 where the hypha was very short. 

 A : a and b, two hyphae growing 

 almost parallel to one another. 

 B : a has sent out a short branch 

 which happens to be growing 

 obliquely toward b. C : in response 

 to a stimulus from the branch- 

 hypha, 6 has put out an opposing 

 peg. D : the short hypha and the 

 peg have fused. Fifteen minutes 

 elapsed between stages B and D. 

 Magnification, 434. 



