w ■ 



ISOETES JAPONICii, A. BE. 



353 



traclieids produced at the junction of the first few root- traces (PI. 40. fig 



f7 



From 



this primary meristem the young roots and the primary xylem, phloem, and cortex of 



the rhizophore are differentiated. 



Differentiation of the primary tissues proceeds along three radiating, hut slightly 



ascendi 



t5 



lines, which 



pond to the thr 



main fur 



of the caudex as 



plained above (p. 346 ef seq 



In this way, the stele of the rhizophore becom 



Text-fig. 11. 



hoetes japonica. Diagram showing arrangement of roots on one flank of a lobe of the rhizophorc-stelo. 

 cambium. (For explanation see text.) The consecutive numbers denote the succession of roots on one flank 

 of a Btelar lobe, whereas the numbers 1/7, 13, 19, etc., denote the succession of roots on the plant. Compare 



text-fig. 10. 



I 



distinctly three-lobed, each lobe appearing irregularly triangular in a radial longitudinal 

 section of the caudex cut in the plane of the corresponding main furrow. 



The young roots are differentiated from the primary meristem of the rhizophore in 

 rows (hereafter referred to as ' series ') roughly parallel to the lower edge of the stelar 

 lo])c ; these series rise in acropetal succession (text-fig. 11). All the roots belonging to 



3e 2 



