412 



BOTANY OF THE LIVING PLANT 



Peronosporales is not unlike that seen in Vaucheria : the former do not 

 liberate free spermatozoids but transfer a single gamete by a tube, as 

 in the higher land-living Plants. The oogonium retains its character, 

 as in Vaucheria. Such considerations may be held to justify the 

 recognition of Fungi included among the Oomycetes as possibly of 



1 Z 



Fig. 3tt. 



Monoblepharis sphaerica. End of a filament with terminal oogonium (o) and an 

 antheridium (a), i, before formation of the gametes. 2, spermatozoids (s) escaping 

 and approaching the opening of the oogonium. 3, osp, ripe zygote and an empty 

 antheridium. (After Cornu. x 800.) (From Strasburger.) 



Siphonaceous origin, from types already advanced in their sexuality. 

 On the other hand it has been suggested that the origin of the Phy- 

 comycetes is to be sought among the colourless Protophyta and that 

 they have developed along lines parallel to, but independent of, those 

 leading to the Green Algae. 



PHYCOMYCETES.— (b) ZYGOMYCETES. 



The Mucors. 



The Zygomycetes include many common Moulds. They are mostly 

 saprophytes, though some of them are parasites not only on other 

 plants and animals, but even on one another. They are characterised 

 first by their coarse non-septate hyphae, but more particularly by 

 the manner of their sexual reproduction, which results from the 

 fusion of two similar, multinucleate branch-endings, to form a single 

 large resting-spore, or zygospore. The chief representatives are 

 the Mucors (Mucorales) found on decaying organic matter in moist 

 circumstances. If moist bread, horse-duns:, brewer's grains or 

 other organic substances be kept warm for a day or two under a 

 bell-glass, Mucorineous Moulds will almost certainly appear. They 



