HYPHAL FUSIONS AND CLAMP-CONNEXIONS 153 



Fig. 84. — Mucor mucedo, one of the heterotliallic Mucorineae. Two monosporous 

 mycelia of opposite sex, one belonging to a ( + ) sexual strain and the other to 

 a ( — ) sexual strain, meeting and forming a line of zygospores along the area of 

 contact. To show the absence of hyphal fusions in either of the two mycelia, 

 and also the absence of hyphal fusions' between the two mycelia except where 

 such fusions are necessary for tlie union of gametes and the consequent pro- 

 duction of zygospores. From the lower left passing upwards obliquely to the 

 right may be seen : young zygophores approaching, meeting, and forming 

 progametes ; the formation of walls separating the gametes from the suspensors ; 

 the disappearance of the central wall separating the two gametes ; and the 

 mature, rough-coated zygospore which has been formed as a result of the fusion 

 of tlie gametes. After A. F. Blakeslee. Copied in black-and-white by the 

 author from the Tabulae Botanicae published by Gebriider Borntraeger in 

 Berlin. Highly magnified. 



