& 
as to form mycorhizas. A mycorhiza consists of the structure 
tissues just underneath the epidermis. Branches of the tubes or| 
hyphae are sent out through the root-hairs into the soil, and the 
two plants work in partnership to accomplish nutrition. The 
fungus takes up the products of decaying leaves and or: rganic 
matter in the soil, carries them into the root, yielding the greater! 
portion to the higher plant, which may actually get all of its food 
from its minute associate. Some of this food, however, is built up 
into starch and sugar, which is given back to the fungus. The 
higher plant thus take the crude material given it by the fungus 
and makes it into substances which the fungus is unable to con- 
struct, but which form a very valuable food for it. In addition 
to this advantage to the fungus the root offers it a habitat in 
which it is free from many dangers it would encounter in the soil. 
The nicety of attention necessary to the successful culture of 
most orchids is doubtless due to the fact that not only must the 
proper conditions of water and temperature be offered the higher 
plant, but its unseen associate must be provided with exactly the 
proper soil and food. 
he fungi which inhabit the hanging roots of the epiphytic 
orchids bear the same relation to them, though many inexperi- 
ence writers ne described them as parasites, 
€ cooperation of the fungus the orchid is relieved from 
the heres struggle to win its food from the soil necessary n- 
aided species, and the great variations and marked characteristics 
of the leaves and flowers of this group may be due in part to its 
method of nutrition. Althou Bie not Saba known, the varia- 
tions of the underground organs are almost as great as those of 
the aérial parts. Thus the eee Ces have lost 
their roots pane and the underground coralloid formations 
which gives them their name, are really short branches serving 
the purpose - roots and inhabited by a fungus. Some of the 
