148 PHARMACEUTICAL BOTANY 
or marsh habit they are medium-sized, while in those which 
live entirely in the water (Aydrophytes) they are of large size and 
more or less rounded. 
INTERNAL SECRETION GLANDS AND RESERVOIRS 
These structures are either found as globular cavities as in 
Orange and Lemon Peel and Eucalyptus leaves, containing oil 
Seness 
Y} 
NW), 
Fic. 85.—Cross section Fic. 86.—Lysigenous gland 
through a portion of Orange in the leaf of Dictamnus fraxinella, 
Peel showing the cavity of an B, young glands, with cells 
internal, schizogenous glob- beginning to secrete oil; C, 
ular gland at g; crystals of mature gland where the secreting 
hesperidin at A; membrane cells have broken down and left 
crystals of calcium oxalate their secretion in the cavity thus 
at k. (After Tschisch and ' formed; o, large drop of secreted 
Oesterle.) oil. (Stevens after Sachs.) 
or oil and resin, when they are called internal glands, or, as tube- 
like spaces filled with hydrocarbon principles, such as are found 
in Pine leaves and stems, when they sometimes receive the name 
of secretion canals or reservoirs. In the Parsley family these canals 
are found in the fruits, where they are called witte. Occasion- 
ally they are named according to the nature of their contents— 
resin or oil canal, reservoir, etc. The internal glands usually 
arise by the division of a cell or group of cells of the ground 
