iqiq] 



WA TERM A N—ROO T S VS TEMS 



35 



the 2-year-old specimen a, barely 2 ft. away, and the absence of 

 prominent laterals is very marked. Cases of extreme elongation 

 were occasionally observed, as in fig. 6. In the specimen figured, 

 the root came in contact with a decaying grass rhizome and turned 

 back at a sharp angle, following the rhizome for about 60 cm. In a 

 similar case the root did not make such a sharp angle, but followed 

 the rhizome for an even greater distance. It should be noted in 



^r-^^:;^. 



Fig. 



Fig. s 



Figs. 4, 5. — Priinus pumila: fig. 4, showing relation of roots to buried plant parts; 

 fig. 5a, 2 years old, which grew in normal dune sand; b, same, 3 years old, which grew 

 in sand with interbedded black laj'ers. 



both cases that the size of the shoot was not at all in proportion to 

 the length of the root. 



In these cases the relation of the root to the organic matter is not 

 clear. Generally there is little penetration of the tissue of the 

 decaying organ. There are occasionally short laterals clasping 

 the foreign body, frequently passing under a sheathing leaf or a 

 disorganized epidermis, and in cases of extreme decay adjusting 

 themselves to the easy passages formed by the disintegration of the 

 middle lamella of the cell walls. There are no indications of haus- 

 toria or of actual penetration of cell walls. In black layers and 



