246 VEGETABLE PHYSIOLOGY 
ing to the natural orders Capparidacee and Tropeolacea, 
the glandular cell divides several times to form a little mass 
or nodule of secreting cells, which must be regarded as a 
rudimentary gland, though it is not provided with any 
definite outlet or duct. 
In the seed of the cereal grasses there is a special 
‘organ separating the embryo from the endosperm. This 
structure, which is a modification of part of the cotyledon, 
is known as the scutellum (fig. 119) ; its function is to effect 
the absorption of the nutritive material of the endosperm, 
and supply it to the growing embryo. This scutellum is 
covered on its outer face, which is in contact with the 
Fic, 120.—SECTION OF PORTION OF 
Fie, 119.—SEctTIon oF OAT-GRAIN. ScuTELLUM OF BARLEY, SHOWING 
p, plumule; 7, radicle; s, scutellum. THE SECRETING EPITHELIUM. 
endosperm, by a layer of cylindrical cells, whose long axis 
is at right angles to the surface (fig. 120). These cells are 
very granular in appearance, and form a very marked 
secreting structure, producing two enzymes, which are sub- 
sequently discharged into the endosperm to effect the diges- 
tion which must precede absorption. The aleurone layer of 
the same grain (fig. 121), which has already been described, 
is also a secreting layer, resembling the outer layer of the 
scutellum in several respects.. 
The tentacles of the leaves of Drosera, to which allusion 
has already been made, are very definitely secreting 
structures ; in addition to preparing an enzyme they pro- 
