Vol. 46 : No. 5 
BULLETIN 
OF THE 
TORREY BOTANICAL CLUB 
MAY, 1919 
Mucilage or slime formation in the cacti 
E. GRACE STEWART 
(WITH PLATE 8) 
The cellular processes involved in the formation of plant slimes, 
of gums, and of resins are subjects which have attracted the atten- 
tion of many investigators. 
Pfeffer (16) in his ‘‘Physiology of Plants’’ states in general 
that mucilage may be formed by synthesis or by decomposition 
as when the cell wall becomes mucilaginous. He also accepts the 
doctrine that mucilage is often formed in the interior of the cell. 
Karsten (7) claims that the formation of cork, gum, slime, etc., 
‘s due to processes of intussusception going on in the protoplasm. 
Tschirch (21) has emphasized the conclusion that in the cell wall 
there is a specialized layer next the cuticle which he calls the 
resinogenous layer and in which so-called secretions are formed. 
Of the earlier investigators, Cramer (2), Von Mohl (22), 
Nageli (15), Hofmeister (6), Wigand (24), Schlacht (17), Frank 
(4), and De Bary (3), were of the opinion that mucilage building 
is a disorganization process occurring in the cell wall. The trans- 
formation into mucilage they all agreed began in the outer part of 
the wall and worked toward the inside. Hofmeister (6) believed 
that the cell walls became thickened by the apposition of new 
layers, hence the striated appearance of the jelly. Frank (4) 
found that in the bulbs of orchids mucilage developed from the cell 
contents in a crystal-bearing cell about a bundle of crystals which 
finally disappear. In other plants he thought the gum was formed 


[The Bulletin for April (46: 107-156) was issued May 1, 1919. 
157 
