1907] HOLM 



RHEXIA 



i 



5 



4 



H 



the primary root withers with the exception of the two lateral swollen 

 branches, which winter over as two separate roots* 



In the following spring a young shoot develops, with scale-like, 

 opposite leaves at the basal nodes, and with several pairs of secondary 

 roots from the nodes, while a dark-colored tuberous body occurs at 

 the base of the shoot. One or more of the secondary roots soon com- 

 mence to increase in thickness, forming fusiform tubers like the 

 one described above on the root of the seedling. Fig, 2 shows a 

 root-shoot; the short, dark tuber at the base of the shoot represents 

 the lateral tuber of the seedling (r in jig. i), and the shoot is developed 

 not from the base of the tuber but from its upper face. If the shoot 

 had continued the axis of the swollen root, there would have been a 

 persistent primary root, but such a case was not observed ; the shoot 

 invariably occupied the position shown on the root marked r in fig. 2, 

 where a bud is seen near the base on the upper face of the tuber. 

 This bud is to develop a new and independent plant during the next year. 



The specimen thus described {jig. 2) represents the root-shoot of 

 the seedling and lives only one year, the persisting part belonging to a 



secondary root. 



H 



development 



and the tuberous roots much larger. The secondary roots develop 

 in pairs from the nodes, betw^een the opposite scale-like leaves. These 

 foots are quite long, branch freely, and are able to produce shoots 

 as described above. Although the underground portion of the stem 

 bears several leaves, none of these were found to subtend buds, and 

 the shoot dies down completely at the end of the season. The tuber- 

 ous roots, on the other hand, may live for three years, if not longer; 



When 



H 



An 



{H 



ring stage is shown in fig. 5. The tuber occupies 

 here a horizontal position, and the shoots for the next year arc already 

 visible as buds on small stems with scale-like leaves and quite distinct 

 intemodes; the place of development of these minute shoots is along 

 the upper face of the root. It is only when the tuber occupies a 

 more or less vertical position that the shoots show a tendency to push 

 out from near the apex, as may be seen in iig. 3. 



