THE ROOT-SYSTEM OF IMPATIENS ROYLEI. 499 
third node also. Consequently, the stem had a jointed appearance for the 
first four internodes, and then it regained its vertical position. Traces of 
adventitious roots appeared above many of these bent nodes, but the roots 
rarely emerged from the stem ; at the best they were slender and short 
(text-fig. 7). 
There are always some weak straggling specimens, small and incapable of 
self-support. These trail along the ground for two or three internodes, 
producing roots from the hypocotyl and from the under surface at the first 
and second nodes, and also in rare instances from the first epicotyledonary 
internode. In these beds of plants it is very exceptional to find roots 
developed from the lateral branches, since the latter are undersized and 
feeble. 
№ 
Fig. 7,—Plant bent at first and second nodes. a.r., adventitious roots. 
E. In plants with slit internodes. 
Passing now from perfectly whole plants, whether upright or bent, we 
come to plants which show a longitudinal slitting of the internode. This 
feature is of common occurrence in the species, and may be due either to 
the disturbance of the osmotic tissue tensions caused by the formation of a 
fistular cavity, ог bv mechanical injury. An internode may show from one 
to four slits extending down the greater part of its length. The hypocotyl 
and the first and second internodes are most frequently affected. 
Adventitious roots sometimes develop at the node just above the slit 
region on the side of the greatest disturbance, even though the stem is 
vertical (text-fig. 8). They arise, as is the case in bent plants, just above the 
node, but they never attain a great length (the maximum length noted was 
half a centimetre). 
