= PIGMENTS 155 
Suberin 
Cutin 
Chlorophyll (chlorophyllan) 
Carotin (Xanthophyll) 
CocHss 
This is the name applied to 
what is probably a mixture of 
several fatty acids including 
the following: Phellonic, phloe- 
onic and suberice (CsH,40s). 
Their presence in the cell walls 
waterproofs them. 
This is a fatty substance or 
substances related to the fore- 
going and waterproofing the 
epidermal cell walls in which 
it is deposited. 
This is a blue-green pigment 
occurring only in chloroplasts 
(or in such Myxophyceae as 
lack definite chloroplasts in 
minute particles in the cyto- 
plasm). It is the most im- 
portant plant pigment, ab- 
sorbing certain light rays and 
transforming the energy into 
the chemical energy used in 
photosynthesis. It is formed 
(with rare exceptions) only in 
the light and is itself quickly 
destroyed by bright light. It 
contains no iron but the plant 
requires iron for its produc- 
tion. Its chemical composi- 
tion is not exactly known but 
it seems to be closely related 
to haemoglobin. Itisinsoluble 
in water but soluble in alcohol, 
ether, petroleum ether, gaso- 
line, ete. Probably “chloro- 
phyll” is not one but a group 
of closely similar compounds. 
Under the name Xanthophyll 
this substance is associated in 
small or large proportions 
with chloophyll wherrever the 
latter occurs, the mixture giv- 
