advanced in the median cotyledonary trace a 
the laterals. 
In the short axis of the embryo it is difficnlt to fix on the 
exact area at which lignification first appears. Examination 
of later stages shows the maximnm lignification of the coty¬ 
ledonary xylem at the collet area, and that the lignification 
subsequently spreads downwards into the primary root and 
upwards into the hypocotyL The collet area is also the first 
to show a vascular cambium and the maximum parenchy- 
‘IT"'' “ therefore Wars to he the centre of 
activity of the seedling axis. 
reaches the- he of th « cotyledonary xylem 
reaches the maximum at the collet area mav however still 
noZ rrr poill ‘ •» »• cotyledonary 
be a 
r any 
There is the Dosa;niHf^ nce *^e area. 
■Pay be purely respoL T “ ° f lignification 
seedlings, in which case 1 •! , ’ ,rem '“ to of the 
- r ion Of 
“ wX’S” 1 *■ 
from root to cotyledons. ° f bgmfied elements exist 
Tie epicotyledonary strand. .1 
~w a definite (UracHon of ^ ~ » ‘-a primary 
eplco^strand begins at the 
- ^^euof^ror^rr 
