476 BOTANICAL GAZETTE [DECEMBER 
including the hardy mid-rootstock, with radial canals between the 
longitudinal canals of the two series. Only the outer of the two 
series of canals is found in the lowest portion of the rootstock and 
the subsidiary roots. A twofold series of canals is found in the 
stem and leaves, an outer series in the sinuses of the cortex opposite 
the interfascicular regions, and a second inner series in the pith 
opposite the hadrome elements. The root canals and the stem 
canals arise as two separate systems and remain distinct. The 
resin canals do not arise until long after resin is formed in the 
meristem. 
3. Balsamoresene and balsamoresinic acid are formed in B. sagit- 
tata from inulin, probably by polymerization and reduction. The 
resene and resinic acid are essentially toxic in nature. The resene 
is the immediate substance from which resinic acid is formed. The 
secretory process is dependent on physiological activity in the meri- 
stem of the plant, in which inulin is used in anabolism and resene 
and resinic acid are derived as waste products in the plant. The 
resinic acid and resene are transferred to the secretory canals, 
where they are stored. 
4. To summarize, the study of B. sagittata, with especial empha- 
sis to the meaning of resin secretion, has developed certain facts 
regarding the purpose of resin secretion. In the growth of the 
plant a polysaccharide, inulin, produced during photosynthesis, is 
broken down, causing a by-product, balsamoresene, to be produced. 
This resene is changed to resinic acid. On account of the probable 
toxic nature of the resene and resinic acid to the plant, they are 
translocated to schizogenously formed ducts of endodermal origin, 
where they are stored as resinic acid. 
UNIVERSITY OF ILLINOIS 
URBANA, ILL. 
LITERATURE CITED 
1. BAEYER, ApotpH, Uber Condensation und Polymerie. Ann. Chem. 
Suppl. 5:79-95. 1867. 
2. CALVERT, AGNxs, and Boonie, L. A., On laticiferous tissue in the pith of 
Manihot Glaziovii and on the presence of nuclei in the tissues. Ann. 
Botany 1:55-62. pl. r. 1887. 
