PLANT TISSUES 
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gated and more or less obtusely or taper ended, its component ele¬ 
ments are termed Scierenchyma fibers. These fibers are frequently 
spindle-shaped, contain air and exhibit oblique slits in their walls. 
They are either polygonal, rectangular or somewhat rounded in 
Pig. 43. —Scierenchyma fibers from different sources. 1, From powdered 
cinnamon bark; 2, End of bast fiber of flax stem showing transverse markings 
(6); 3, middle portion of flax fiber showing characteristic cross markings at b; 4, 
bast fiber from cinchona bark; 5, branched bast fiber from choke cherry bark; 
6, above, end, and below, median portion of bast fiber of jute. All highly mag¬ 
nified. 
transverse section. They occur in various parts of roots, stems, 
leaves, fruits and seeds as supporting elements. When scierenchyma 
fibers occur in the xylem region of fibro-vascular bundles they are 
termed Wood Fibers; when they appear in the ph'osm region, 
Bast Fibers. 
