30 ' BOTANICAL GAZETTE [july 



this species are able to persist more than one season, since the buds 

 borne on the basal nodes remain active and produce new shoots in the 

 next year. But, as stated above, young as well as old shoots may be 

 observed among each other on the same root, and consequently on 

 its upper face. Two to four slender secondary roots develop from 

 the basal internodes of the older shoots. No specimen was found 

 in which there was any indication of the primary root, and it would 

 be very interesting to know whether the seedling of this species 

 behaves in the same way as that of R. virginica. 



THE INTERNAL STRUCTURE OF THE VEGETATIVE ORGANS 



The roots 



very 



may 



rmis 



produce hairs; the exodermis consists of a single layer of thin- 

 walled, pentagonal cells that are larger than those of the adjoining 

 cortex. The cortex is of five layers of thin-walled cells, with wide, 

 rhombic, intercellular soaces: druids but no denosits of starch were 



pericamb 



rays 



observed. A thin-walled endodcrmis and a continuous 



4 



surround five groups of leptome, alternating with fi 



of hadrome; while the center of the stele is occupied by a narrow 



cylinder of moderately thickened conjunctive tissue. 



In the thicker and stronger roots, lateral or secondary, the cortex 

 frequently collapses radially, and there is increase in thickness; how- 

 ever they do not increase as much as do the roots of the foregoing 

 species, and never become tuberous. Cork is developed when the 

 secondary leptome and hadrome begin to appear, arising from the 

 pericambium. 



As stated above, the roots of this species are very long and grow 

 horizontally and in several cases an excentric growth was noted. 

 In old roots the epidermis and exodermis are partly thrown oflF, and 

 the corlcx is collapsed almost throughout. The stele, however, is 

 protected by four or more strata of cork, within which there arc stereids 

 scattered in small groups outside the leptome; the secondary rays 



from 



also 



u 



in the central part of the stele. No starch was observed 



