121 
PLANT TISSUES 
They are either polygonal, 
slits or rounded pores in their walls. 
They 
rectangular or somewhat rounded in transverse section. 
om 
(KALA 
re. 
\ A 
ad 
ors 
rat 
or 
isi 
i. 
o 
| 
ar 
7 @ 
a by 
saaL® 
hi 
— 
Tr 
of Tee 
“2 
07a 
rt) 
qi 
Ld 
pom 
is Citing 
RQ 
~~ 
TD = ae, 
tt Ley 
hy 
19g 
PS —— i 
wa 
a) ~ @ = 
“CT 
*. 
we (i 
/ a” Cages 
ye, pom @ 
oMet-t< 
ae ™ =~ | P 
“hs 2 
a 
ae rai 
BO O30 
L 
coat 
Nedlog hua) 
Pee. 
‘ae 
nal pe 
ai cst 
A 
Bes 
ines of i 
Walce 
Pe 
re 
ton 
ws 
Fic. 62.—Transverse section of a portion of the wood of the Black Ash. 
A, 
bers; mr, medullary 
wf, wood fi 
170. Note the polygonal to rounded-polygonal shape of the 
summer wood; B, autumn wood; C, spring wood. 
wood fibers in cross section. 
ray; tr, tracheae. 
occur in various par 
supporting elements. 
ts of roots, stems, leaves, fruits and seeds as 
When sclerenchyma fibers occur in the 
, they are termed Xylem 
xylem region of fibro-vascular bundles 
