PRACTICAL BOTANY. 



2. The four Primary Xylem groups retain their 

 original position. 



3. Four large wedges of Secondary Xylem have 

 originated internally from the four cambium zones. 

 These are separated from one another laterally by 



4. Four broad Parenchymatous rays, which lie 

 on the same radii as the primary xylem. Outside the 

 xylem is 



5. The Cambium, having similar characters to that 

 of the stem, and giving rise peripherally to 



6. Secondary Phloem. Note if possible 



7. The four groups of Primary Phloem now sepa- 

 rated from the primary xylem, but still on radii alter- 

 nating with the latter. The section is bounded by 



8. Cork with a Cork-cambium. 



Apex of the Root. 



Type I. Cut thin median longitudinal sections of 

 the apex of the radicle of the straight embryo of 

 Helianthus. 



[The arrangement of the meristem at the apex of 

 the radicle of the embryo is similar to that of the apex 

 of the growing root, and the former is chosen in this 

 case as it is much easier to make preparations from it 

 than from the growing root. The sections are of little 

 use unless they are accurately median.] 



Treat the sections with potash for ten minutes or 

 more : wash with water, and mount in glycerine : 

 examine with a low power, and observe that 



1. The mass of tissue is composed of thin-walled 

 cells, arranged regularly in longitudinal rows. 



