


64 FLOWERING PLANTS 
comparatively small portion of the stem, and shows a slight 
amount of lignification. In many water-plants lignin is not 
found in the walls of wood cells. : 
a 
ce 
oS 
Seeee: 
scour aN 
ee. ras 
@ 
\ 
ee 
ay 
st 
Ca 
St 
S 
2 
wan 
ot 
son 
ae 
sis 
‘eS 
Cy 
iA 
Se 
& 
a 
Se 
A> 
aS 

Fic. 33.—STELE OF Hipruris, TRANSVERSE SECTION. (High power.) 
cort, cortical tissue-; end, endodermis ; b, bast ; w, weod; p, pith. 
In one or other of these ways the minute structure of the 
stem 1s adapted to the habitat of the plant. 
