MUCORINI 



641 



.sexual spores occur in the family, including chlamydospores, repro- 

 ductive cells formed within the ordinary cells of the hyphse. Sexual 

 reproduction takes place by means of zyyospores (C), but is at 

 present known only in a few species. Either from ordinary hyplue 

 or from sporangiophores spring a pair of short branches, the 

 extremities of which become firmly attached to one another. These 



FIG. 479. B, mycele (three days old) of Phycomyces nitens, grown in a drop of 

 mucilage with a decoction of plums ; the finest ramifications are omitted ; g, the 

 conidiophore of Mucor mucedo in optical longitudinal section ; C, a germinating 

 zygospore of Mucor mucedo ; the germ-tube, k, puts out a lateral conidiophore, g. 

 In D are conjugating branches, b &, the extremities of which, a a, though they have 

 not yet coalesced, are already cut off by transverse walls; the zygospore is formed 

 from the coalescence of the cells a a. A, C, D, after Brefeld, greatly magnified ; 

 B, from nature, slightly magnified. From Goebel's ' Outlines of Classification 

 and Special Morphology.' 



swell out greatly into an obconical form, on account of the passage 

 into them of a large amount of nutrient material. A larger or 

 smaller piece is then cut off from each of them by a transverse 

 wall ; the median cell- wall which separates them disappears, and the 

 two terminal portions thus cut off coalesce to form the zygospore, 



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