x1] STONEWORTS, AND PEPPERWORTS. 173 
of the spore-case is devoted to the large single spores ; 
the upper produces the smaller. numerous granules, 
which ultimately yield spermatozoids, which fertilise 
the larger spores. ‘This spore-case is represented at 
fig. 133. 
Pilularia is more frequent in the south of Britain 
than /soétes, but it requires careful searching amongst 
the sedges to discover it. Both these 
plants are easily cultivated, /soétes form- 
ing a suitable object for the bottom of 
an aquarium. They belong, as we have 
stated, to the order MWarsileace@, one 
species of which, JZ. macropus, affords 
the fruit called Nardoo, which the Australian abori- 
gines made up into a coarse kind of bread, and to 
which a melancholy interest attaches, When the 
exploring expedition of Messrs. Burke, Wills, and 
King had crossed the Australian continent from Mel- 
bourne to the Gulf of Carpentaria, they were reduced 
to sore straits on the return journey, finally perishing 
of starvation. ‘This was their last resource, and Mr. 
King, who survived, brought some of the spores with 
him to Melbourne: there are specimens at Kew 
which were raised from these spores, 
