LYCOPERSICUM ESCULENTUM 



573 



tion is definitely attained and a bicollateral cotyledonary bundle 

 is formed. (Fig. i99.) The traces of the first foliage leaves 

 above the CDtyledonary plate consist of bicollateral bundles that 

 are completely endarch. These anastomose with the vascular 

 elements of the hypocotyl at and slightly below^ the cotyledonary 

 node. 



Secondary Roots. — The lateral and adventitious roots are 

 commonly tetrarch, occasionally pentarch. (Fig. 300.) Second- 



FiG. }oo. Transection of adventitious root with tetrarch stele : ca, cambium ; co, cortex ; 

 csp, Casparian strip; en, endodermis; ep, epidermis; pel, pericycle; ph, phloem; ra, ray; 

 xy I, primary xylem; xy z, secondary xylem. 



ary thickening is initiated in the usual 

 parenchyma centrad to the primary 

 radiating arms of protoxylem. As a 

 four wedge-shaped sectors of secondary 

 separated from one another by pericycl 

 region, the pericycle is uniseriate or 

 The endodermis and cortex persist for 



manner in the fundamental 

 phloem and between the 

 result of cambial activity, 

 xylem are formed which are 

 ic rays. Except in the ray 



occasionally two-layered. 



some time after secondary 



