THE STORAGE OF RESERVE MATERIALS 245 
During germination it splits up into benzoyl aldehyde, 
hydrocyanic (prussic) acid, and grape-sugar. Many such 
bodies are known, and they are somewhat widely distri- 
buted. Some occur in seeds, but they are more frequently 
represented in the reservoirs contained in fleshy roots and 
stems. Many plants belonging to the Cructfere and several 
allied orders are particularly rich in reserve materials belong- 
ing to this group. Sinigrin, or myronate of potash, is the 
principal glucoside which they contain. It splits up into 
sulphocyanate of allyl, srape-sugar, and hydrogen-potassium- 
sulphate. 
The nutritive value of these bodies is partly due to the 
sugar which they yield on decomposition. The evidence 
that the other products can minister to nutrition is not 
very complete, though it seems satisfactory in certain 
cases. 
Fats or oils are frequently stored as reserve food-stufts 
in different plants. The distribution of this material is 
very varied, though, as in so many other cases, the seed is 
the most general place of deposition. Many seeds—that 
for instance of the castor-oil plant—contain as much as 
60 per cent. of their dry weight of oil, which is non-volatile. 
Others contain as little as 2 per cent., and between 
these limits very varying amounts may be found. When 
the oil is in great preponderance, it is usual for no other 
form of carbonaceous reserve to be present ; in cases where 
but little oil occurs starch is usually found as well, as in so 
many of the Leguminose. The Crucifere as a group often 
contain oil in fairly large quantity. As a rule nitrogenous 
reserves in the shape of aleurone grains accompany the oil. 
In other places than seeds large deposits of oil often 
occur, though their purpose is not so obvious. We have 
them in large amount in the pericarps of certain fruits, 
such as the olive ; in the petals of many flowers, e.g. Funkia 
and Ormithogalum ; in the leaves of some of the Agaves, the 
roots of Oncidium, &c. They can hardly be regarded in 
some cases as truly reserve materials, being perhaps more 
