38 
PLANT MORPHOLOGY. 
phenolic dyes, as alizarin, if previously treated with 
basic mordants, as basic salts of aluminum, etc. 
According to their origin in the plant, or their 
behavior toward reagents, the cellulose walls may be 
divided into the following groups : (1) Lignocellulose 
walls; (2) protective cellulose walls ; (3) reserve cellu- 
lose walls ; (4) mucilage cellulose walls, and (5) mineral 
cellulose walls. 
(1) Lignocellulose walls are composed of true cellulose 
and a non-cellulose (the so-called lignin or lignone), 
these constituting the woody (so-called lignified) por 
tion of plants and, in some instances, also the bast por- 
tion of the bark. The lignocelluloses are colored yel- 
low with chlor-zinc-iodide, or iodine and sulphuric 
acid. On account of their containing, in some in- 
stances, furfurol, coniferin, vanillin, cinnamic aldehyde, 
benzaldehyde and other aldehydic substances, they 
give definite color-reactions, particularly with the ani- 
line stains, as fuchsin, safranin, gentian violet, aniline 
blue, methylene blue, etc. 
A 2 per cent, phloroglucin solution, used in conjunc- 
tion with hydrochloric acid, gives a reddish-violet color 
with the lignocelluloses, although there are some cel- 
luloses of this class which do not respond to this test, 
as the bast fibers of linum; while in other plants 
phloroglucin may occur as a constituent of the cells. 
Aniline hydrochloride with hydrochloric acid and 
aniline sulphate with sulphuric acid produce a golden 
yellow Color in cell walls containing lignocelluloses. 
(2) Protective cellulose walls are composed of mixtures 
of lignocellulose with oils and waxes, and frequently 
contain in addition tannin, vanillin and other com- 
pounds. In the cuticle or epidermis of leaves and 
green stems, the cellulose is associated with a fatty 
compound known as cutin or cutose, while in the cork 
