


62 : FLOWERING PLANTS 
SUMMARY OF Stem TIssuEs. 
Meristematic. Permanent. 
iS Dermatogen giving rise to Epidermis. 
2. Periblem aS , Cortical Parenchyma and En- 
: dodermis. 
At | : 
Apex | _ | Pericycle. 
3 S Biome : 2 eile | Fibro-vascular tissue 
and medullary rays. 
| Pith. | 
Cambium = , Secondary bast and secondary 
wood. 
Gia oe The stem of a xerophytic plant differs in one or 
Xerophytes. two well-marked particulars from the mesophytic 
stems just described. | . 
Fig. 31 is a drawing of a transverse section of Salicornia, a 
plant growing on muddy sea-shores and in salt marshes. It 
has no leaves, so that the stem practically combines the func- 
tions of leaf and stem. 






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Fic, 31.—SALICORNIA, TRANSVERSE SECTION oF Harr A STEM. 
(High power. ) 
e, epidermis ; st, stomate ; int, intercellular space ; p.p, palisade paren- | 
chyma with chlorophyll ; w.s.¢, water-storage tissue ; end, endodermis ; 
pr, pericycle ; 6, bast; cb, cambium ; p.w, primary wood ; w, secondary 
wood ; p, pith. 
The most striking features of this stem are: 
1. The thick cuticle of the epidermis and the stomata, com- 
municating with the intercellular spaces. 

