PLANT STUDIES 
habit is called parthenogenesis, which means reproduction 
by an egg without fertilization. 
FIG. 233. A common water mould (Saprolegnia): A, a fly from which mycelial fila- 
ments of the parasite are growing; B, tip of a branch organized as a sporangium; 
C, sporangium discharging biciliate zoospores; F, oogonium with antheridium in 
contact, the tube having penetrated to the egg; D and E, oogonia with several 
eggs. A-C after THURET, D-F after DEBARY. 
181. Mucor. One of the most common of the Mucors, or 
" black moulds," forms white furry growths on damp bread, 
preserved fruits, manure heaps, etc. It is therefore a 
saprophyte, the crenocytic mycelium branching extensively 
through the substratum (Fig. 234). 
