yt ‘ \ ."% x Soran. > : : wn . 
- - > 7 P : Mi & $e; 4s 
46 
order that a cork-tissue may be formed, which closes the wound and 
_prévents the decay of the cutting. | Bae. 
Larger wounds, as, for instance, when branches are cut off, are often 
closed by the formation of elevated cushion-shaped masses of cells, not 
consisting entirely of cork-tissue, which are fresh formed over the whole — 
surface of the wound. Such a tissue is called an overgrowth, and is | eo 
seen especially in the beech, silver fir, and lime (Fig. 68). Ofasimilar 
structural and Physiological Botany. — 
CRO = 3) e : a 
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2) 
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MOLO) 
w7-{2 Oo 
Fic. 68.—Overgrowth Fic. 69.—Portion of a scalariform Fic. 70.—Pitted vascu- 
oni a branch cut 
through obliquely, 
(natural size.) 
vessel from the brake, Pteris 
‘aquilina ; ss the transverse divi- 
sion-wall broken through in a 
reticulate manner. (x 370.) 
lar cell from the stem 
of a grass, Phragmites 
communis, with nu- 
inerous small bordered 
| pits. (x 400.) 
nature is the callus, to which we shall recur when speaking of repro- 
duction by means of cuttings. 
Smaller developments of cork at particular points of the 
surface, which assume characteristic forms according to the _ 
species, are termed Jentzce/s. They appear in young branches 
before the formation of periderm, and occur in the birch, 
beech, elder, &c. | beri 
