CONJUGATING FUNGI— PHYCOMYCETES 



229 



are parasitic on living vegetables. The Saprolegniaceae are 

 aquatic. And the Entomophthoreae are entomogenous. 



The Mucoraceae might be mistaken for moulds if not more 

 closely examined. The erect threads are not conidia-bearers, 

 but sporangiophores, because they support 

 sporangia at their tips ; and these sporangia 

 are nearly globose cells of thin membrane, 

 which enclose the spores, or reproductive 

 bodies (Fig. 104). When fully matured the 

 sporangium is ruptured and the enclosed spores 

 escape. This is the ordinary asexual repro- 

 duction of the Mucors, and all that was really 

 known of them half a century ago. In some 



,, . . .. . . J s . , . Fia. 104.— Mucor. 



cases the fertile branch, or sporangiophore, is 



prolonged into the interior of the sporangium, and becomes a 



columella. 



The sexual reproduction of the Mucoraceae is accomplished 

 by zygospores, resulting from conjugation, and hence they are 

 sometimes characterised as Zygomycetes. In many of the species 

 this form of reproduction has never been traced, but has been 

 accepted from analogy. Two lateral branches resembling each 

 other, and termed archicarps, are concerned in the process. 

 They resemble at first ordinary branches, which approach each 

 other until the tips meet, but as they increase in size they 



become clavate, and 

 are densely filled 

 with protoplasm. 

 At length the ex- 

 treme portion of 

 each archicarp is 

 separated from the 

 basal portion by a 

 transverse septum, 

 each portion acquir- 

 ing a distinctive 

 name, the basal cell 

 being termed the 

 suspensor, and the apical cell the gamete (Fig. 105). At the 

 point where the two gametes meet the separating cell-walls are 



Fig. 105. — Formation of Zygospore. After De Bary. 



