138 
IOWA ACADEMY OF SCIENCES. 
STUDY OP GLANDS IN THE HOP-TREE. 
BY CASSIE M. BIGELOW. 
In studying this plant, the main object has been to bring out 
the characteristics of the glandular structures m Ftelea tri- 
foliata and the differences between the glandular structure of 
this plant and other used in a like way as the hop. 
The hop -tree is grown quite extensively in parts of Russia, 
as a substitute for true hops. It has the same bitter taste, but 
is without the aromatic principle which makes the bitterness of 
true hops so valuable. 
It is also used in bread making as a substitute for hops. It 
does the same thing without giving it exactly the same taste. 
In bread making it prevents the yeast from souring by check- 
ing the fermentation before all the sugar is converted into alco- 
hol and carbon-dioxide. 
The members of the order Rutacem are noted for the conspic- 
uous aromatic properties, as in the prickly ash, Ruta, Dictam- 
nus, orange, lemon, etc. They all have lysigenous passages. 
Ruta, so commonly cultivated in gardens, is very acrid, some- 
times even blistering the skin, and this acrid substance is found 
in the numerous lysigneous passages produced in the plant. 
The glands of Ruta are situated just under the epidermal 
cells. They are circular in outline, enclosed by layers of 
thin walled, more or less disorganized cells, followed by a layer 
of cells with granular contents. 
The mode of origin of these glands is quite interesting, 
especially when compared with resin canals. DeBary and 
others, who have studied them, find their origin to be as 
follows. 
They can be seen well in sections of young growing leaves 
of either Ruta graveolens, or another nearly related plant, 
Dictamnus fraxinella. 
They appear as roundish spaces or cavities filled with their 
contents (formerly called interior glands), and are produced in 
