128 PRACTICAL BOTANY. 



similar cultivation on fresh horse manure will produce 

 Mucor mucedo. Mucor can be distinguished from other 

 growths, in part by the greater size ; in part by the black 

 color of its spores ; and in part by the fact that in young 

 plants there are no septa except those which cut off 

 the spherical spore-bearing knobs, the sporangia, from 

 their hyphse. In older plants septa are sparingly formed, 

 but are far less numerous than in other growths likely to 

 be present. 



This is the first plant thus far studied among the Fungi 

 which shows even a rudimentary differentiation into root 

 and shoot ; among the Algse a similar differentiation has 

 been noted in the case of the Characeae. The aerial shoots 

 do not show any differentiation into leaves, nor do they 

 in any way function as leaves. They do not contain 

 chlorophyl, and cannot assimilate carbon dioxide, even if 

 it makes its way into them by osmotic action. The root 

 hyphse, on the contrary, show in quite a marked degree 

 something that is similar to the root pressure which is 

 characteristic of the higher plants. They take in water 

 by osmotic action so vigorously that it is forced up into 

 the aerial branches with energy enough, in some cases, to 

 burst through the walls of the sporangia. 



1. Tear off a very little of the growth and mount in 

 water. Examine the mycelium (the interlacing rhizoid 

 portions) and the hyphse (the erect aerial stalks) for 

 septa. Examine the sporangia which tip the hyphse. 

 The cell walls of the older sporangia are densely covered 

 with crystals of calcium oxalate, which dissolve the in- 

 stant they touch the water, setting the inclosed spores 

 free, together with the mucilage which surrounds them 

 in the sporangia. The young sporangia retain their 

 spherical shapes. 



2. Notice an ovoidal projection of the hypha into the 

 sporangium. This is the columella. In some cases where 



